Apparatuses and methods for negative pressure wound therapy

ABSTRACT

Disclosed herein are several embodiments of a negative pressure appliance and methods of using the same in the treatment of wounds. Some embodiments are directed towards wound dressings comprising a liquid and gas permeable transmission layer, an absorbent layer for absorbing wound exudate, the absorbent layer overlying the transmission layer, a gas impermeable cover layer overlying the absorbent layer and comprising a first orifice, wherein the cover layer is moisture vapor permeable. Some embodiments are directed to improved fluidic connectors or suction adapters for connecting to a wound site, for example using softer, kink-free conformable suction adapters.

INCORPORATION BY REFERENCE TO ANY PRIORITY APPLICATIONS

Any and all applications for which a foreign or domestic priority claimis identified in the Application Data Sheet as filed with the presentapplication are hereby incorporated by reference under 37 CFR 1.57.

BACKGROUND OF THE DISCLOSURE Field of the Invention

Embodiments of the present invention relate generally to the treatmentof wounds using negative pressure wound therapy, and more specificallyto an improved apparatus and method thereof.

Description of the Related Art

The treatment of open or chronic wounds that are too large tospontaneously close or otherwise fail to heal by means of applyingnegative pressure to the site of the wound is well known in the art.Negative pressure wound therapy (NPWT) systems currently known in theart commonly involve placing a cover that is impermeable orsemi-permeable to fluids over the wound, using various means to seal thecover to the tissue of the patient surrounding the wound, and connectinga source of negative pressure (such as a vacuum pump) to the cover in amanner so that negative pressure is created and maintained under thecover. It is believed that such negative pressures promote wound healingby facilitating the formation of granulation tissue at the wound siteand assisting the body's normal inflammatory process whilesimultaneously removing excess fluid, which may contain adversecytokines bacteria. However, further improvements in NPWT are needed tofully realize the benefits of treatment.

Many different types of wound dressings are known for aiding in NPWTsystems. These different types of wound dressings include many differenttypes of materials and layers, for example, gauze, pads, foam pads ormulti-layer wound dressings. The wound dressing may be sealed to asuction port providing connection to a length of tubing, which may beused to pump fluid out of the dressing and also to transmit negativepressure from a pump to the wound dressing. Wound exudate and otherpotentially harmful material is extracted from the wound region and mustbe stored for later disposal. A problem associated with many knowntechniques is that a separate canister must be provided for storage ofsuch exudate. Provision of such canisters is costly and bulky and proneto failure.

It has been suggested as a solution to this problem that a liquidimpermeable moisture vapor permeable cover layer can be utilized as anuppermost cover layer for the wound dressing. The air impermeable natureof the cover layer provides a sealing layer over the wound site so thatnegative pressure can be established below the dressing in the region ofthe wound. The moisture vapor permeability of this covering layer isselected so that liquid can constantly evaporate away from the top ofthe dressing. This means that as therapy is continued the dressing doesnot have to take up and hold all liquid exuding from the wound. Rather,some liquid is constantly escaping in the form of moisture vapor fromthe upper environs of the dressing.

Whilst such dressings work well in practice, the continuous evaporationof moisture vapor from the dressing can lead to the problem of crustformation in the dressing. That is to say, because of the continuousdrawing of liquid away from the wound site solid particulate matter ismore prone to formation and accumulation in the dressing. Under certaincircumstances the build-up of such solid material can lead to blockagesforming in the wound dressing in the flowpath between the wound and thesource of negative pressure. This can potentially cause problems in thattherapy may need to be halted to change a dressing if the blockagesreach a critical level.

Further, the stiffness of the suction port in such close proximity tothe wound site can adversely affect the healing process. Patientmovement or pressure onto the wound dressing may bring the healing woundinto contact with the inflexible suction port of the dressing. Suchforce can cause disturbance of a wound bed which can damage a woundsite. This can potentially cause delays in healing of the wound site anddiscomfort for the patient.

It will also be appreciated that the tubing connected to the suctionport is prone to obstruction. The tubing may become obstructed bymovement of the patient, which may cause the tube to bend and form akink or may place pressure onto the tubing, substantially or fullyblocking the flow of fluid through the tubing. This can reduce oreliminate the negative pressure being transmitted to the wound site, andin embodiments employing a separate canister for fluid collection it canalso result in accumulation of excess wound exudate at the wound site.

SUMMARY OF SOME EMBODIMENTS

Embodiments of the invention disclosed herein are directed to a negativepressure appliance and methods of treatment using a negative pressureappliance, and may be useful in the treatment of wounds using negativepressure. It is an aim of certain embodiments of the present inventionto at least partly mitigate the above-mentioned problems.

Certain embodiments of the invention employ a wound dressing capable ofabsorbing and storing wound exudate in conjunction with a pump. Somewound dressing embodiments further comprise a transmission layerconfigured to transmit wound exudates to an absorbent layer disposed inthe wound dressing. Additionally, some embodiments provide for fluidicconnectors and/or suction adapters for connecting a source of negativepressure to a dressing positioned over a wound site. These fluidicconnectors and/or suction adapters offer advantages over the prior art.For example and for illustrative purposes only, some of the embodimentsmay offer a softer, kink-free fluidic connector for connecting a woundsite to a source of negative pressure for treatment. Such a fluidicconnector and/or suction adapter is faster to apply, requiring fewersteps compared to prior art connectors, and offers greater patientcomfort and safety by being soft and conformable, thereby avoidingpressure ulcers and other complications caused by harder connectors.

Certain embodiments provide the advantage that a wound dressing can beused to collect wound exudate generated during a negative pressuretherapy process, whilst extending the useful lifetime of the dressing bytranspiring a water component of the wound exudate. A pump remote fromthe wound dressing can be connected to the wound dressing and reusedwhilst the wound dressing itself is used to collect wound exudate andmay then be disposed of after use.

Certain embodiments provide a wound dressing and/or method of applyingtopical negative pressure in which a flowpath through a wound dressingis kept open so that therapy can be continued for as long as desired bya care giver. In some embodiments, solid material, which may cause ablockage, is prevented from entering a flowpath region in the wounddressing by using a layer of the dressing to act as a bar to suchmaterial. Some embodiments prevent build-up of solid material in aflowpath region of a wound dressing by ensuring that any solid materialthat enters into that flowpath region can always escape into a furtherregion of the dressing.

Certain embodiments of the invention employ fluidic connectors and/orsuction adapters for connecting a source of negative pressure to adressing positioned over a wound site. These fluidic connectors and/orsuction adapters offer advantages over the prior art. For example andfor illustrative purposes only, some of the embodiments may offer asofter, kink-free fluidic connector for connecting a wound site to asource of negative pressure for treatment. Such a fluidic connectorand/or suction offers greater patient comfort and safety by being softand conformable, thereby avoiding pressure ulcers and othercomplications caused by harder connectors.

In one embodiment, a wound treatment apparatus comprises:

-   -   a wound dressing comprising:        -   a wound contact layer configured to carry a pressure            sensitive adhesive;        -   a transmission layer comprising a first 3D fabric material            configured to remain open upon application of negative            pressure to the wound dressing, the transmission layer            overlying the wound contact layer;        -   an absorbent layer for absorbing wound exudate, the            absorbent layer overlying the transmission layer and            comprising an aperture;        -   a cover layer overlying the absorbent layer and comprising            an orifice, wherein the cover layer is moisture vapor            permeable; and    -   a suction adapter comprising:        -   a sealing surface for sealing the suction adapter to the            cover layer of the wound dressing, the sealing surface            comprising an adhesive or weld;        -   wherein the sealing surface is positioned over the orifice            in the cover layer; and        -   wherein the aperture in the absorbent layer is configured to            permit the suction adapter to be in fluidic communication            with the transmission layer; and        -   a bridge having a proximal end and a distal end, the bridge            comprising:        -   a first fluid passage in fluid communication with a source            of negative pressure, the first fluid passage comprising a            second 3D fabric material; and        -   at least one flexible film layer having a proximal and            distal end and configured to surround the first fluid            passage, the distal end of the flexible film connected to            the upper surface of the sealing surface.

Further embodiments further comprise a filter configured tosubstantially prevent wound exudate from entering the bridge; and one ormore spacer elements configured to prevent the suction adapter fromcontacting the transmission layer. In some embodiments, the bridgefurther comprises a second fluid passage positioned above the firstfluid passage, and wherein the at least one flexible film layer isconfigured to surround the first and second fluid passages. In someembodiments, the second fluid passage is connected to an air leak.

Another embodiment provides for a method for treating a woundcomprising:

-   -   providing a wound dressing comprising:        -   a transmission layer comprising a first 3D fabric material;        -   an absorbent layer for absorbing wound exudate, the            absorbent layer overlying the transmission layer;        -   a cover layer overlying the absorbent layer and comprising            an orifice, wherein the cover layer is moisture vapor            permeable;        -   providing a flexible suction adapter comprising:        -   a top layer constructed from a liquid impermeable material;        -   a bottom layer constructed from a liquid impermeable            material;        -   a second 3D fabric material located between the top and            bottom layers;        -   an aperture in the bottom layer in fluid communication with            the second 3D fabric material; and        -   an elongate channel extending between the top and bottom            layers containing the second 3D fabric material, wherein the            top layer, the bottom layer, and the second 3D knitted or 3D            fabric material include enlarged distal ends with the            channel extending in a proximal direction away from the            enlarged distal ends, and wherein the enlarged distal ends            comprise a sealing surface for securing the suction adapter            to the cover layer of the dressing;    -   attaching the flexible suction adapter in fluid communication        with the dressing;    -   positioning the dressing over a wound site to form a sealed        cavity over the wound site; and    -   applying negative pressure to the wound site to draw fluid        through the transmission layer into the absorbent layer.

In some embodiments, applying negative pressure to the wound sitecomprises applying negative pressure from a pump through a connector atthe distal end of the suction adapter, the connector comprising afluidic connector, the negative pressure being transmitted through thesecond 3D fabric material of the suction adapter to the transmissionlayer through the orifice in the cover layer.

In one embodiment, an apparatus to provide suction to a wound sitecomprises:

-   -   a spacer layer comprising a proximal end, an elongate middle        portion and a distal end;    -   a top layer constructed from a liquid impermeable material        provided over the spacer layer;    -   a bottom layer constructed from a liquid impermeable material        provided below the spacer layer, wherein the top layer and the        bottom layer substantially enclose the spacer layer;    -   one or more apertures in the bottom layer beneath the distal end        of the spacer layer;    -   a filter positioned below the distal end of the spacer layer        adjacent the one or more apertures; and    -   a conduit in fluid communication with the proximal end of the        spacer layer.

In further embodiments, the distal end of the spacer layer may beenlarged relative to a width of the elongate middle portion and a widthof the proximal end. The filter may be positioned between the distal endof the spacer layer and the bottom layer. The filter may be below thebottom layer. The spacer layer may comprise one of a 3D knitted or 3Dfabric material, foam, a porous material and non-woven material. In someembodiments, the proximal end of spacer layer may be folded. The conduitmay extend into an opening in the spacer layer. In some embodiments, theopening may comprise an elongated slot. The opening may comprise achannel extending to the proximal end of the spacer layer. The conduitmay extend proximally from the proximal end of the spacer layer, with aportion of the conduit extending between the top and bottom layers. Theconduit may have one or more circumferential ribs to facilitateconnection to the top and bottom layers. In some embodiments, a distalend of the bottom layer may comprise adhesive. In some embodiments, anelongate middle portion of the bottom layer may comprise adhesive.

In further embodiments, the distal end of the bottom layer may beadhered to a wound dressing with the aperture in the bottom layer beingpositioned over an opening in the wound dressing. Some embodiments mayfurther comprise an extension conduit configured to be removablyconnected to the conduit in fluid communication with the proximal end ofthe spacer layer. The top layer may be adhered to the bottom layer toform an elongate channel holding the spacer layer therein.

In some embodiments, the filter may have a perimeter shape correspondingin shape to the distal end of the spacer layer. The distal end of thespacer layer may have a circular shape. The distal ends of the top andbottom layers may have an enlarged distal end similar in shape to anenlarged distal end of the spacer layer. The spacer layer may have asubstantially rectangular cross-sectional dimension. In someembodiments, spacer layer may be adhered to at least one of the top andbottom layers.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A illustrates an embodiment of a negative pressure wound treatmentdressing capable of absorbing and storing wound exudate with a flexiblesuction adapter;

FIG. 1B illustrates a cross section of an embodiment of a negativepressure wound treatment dressing capable of absorbing and storing woundexudate with a flexible suction adapter;

FIG. 2 illustrates an embodiment of a negative pressure wound treatmentsystem employing a wound dressing capable of absorbing and storing woundexudate and a flexible suction adapter;

FIGS. 3A-C illustrate various embodiments of the enlarged end of aflexible suction adapter;

FIGS. 4A-D illustrate the use and application of an embodiment of awound treatment system onto a patient;

FIG. 5A illustrates a top view of an embodiment of a flexible port;

FIG. 5B illustrates a bottom view of an embodiment of a flexible port;

FIG. 5C illustrates a perspective exploded view of an embodiment of aflexible port;

FIG. 6 illustrates an embodiment of a flexible port attached to a wounddressing;

FIG. 7A illustrates a perspective view of an embodiment of a flexibleport;

FIG. 7B illustrates a close up view of an embodiment of the proximal endof the flexible port of FIG. 7A;

FIG. 7C illustrates a close up view of the bottom of the distal end ofthe flexible port of FIG. 7A;

FIGS. 8A-B illustrate various embodiments of the distal end of a conduitwhich may be part of a flexible port;

FIG. 9 illustrates a perspective top view of an ornamental design of oneembodiment of a flexible port as disclosed herein;

FIG. 10 illustrates a top plan view of the flexible port of FIG. 9;

FIG. 11 illustrates a bottom view of the flexible port of FIG. 9;

FIG. 12 is a far side view of the flexible port of FIG. 9;

FIG. 13 is a near side view of the flexible port of FIG. 9;

FIG. 14 is a front view of the flexible port of FIG. 9;

FIG. 15 is a rear view of the flexible port of FIG. 9;

FIG. 16 is an exploded view of the flexible port of FIG. 9;

FIG. 17 illustrates an embodiment of a wound treatment system;

FIGS. 18A-D illustrate the use and application of an embodiment of awound treatment system onto a patient;

FIG. 19A illustrates an embodiment of a wound dressing in cross-section;

FIG. 19B illustrates another embodiment of a wound dressing incross-section;

FIG. 19C illustrates another embodiment of a wound dressing incross-section;

FIGS. 20A-C illustrate a top view of an embodiment of a wound dressingwith a narrow central portion;

FIGS. 21A-F-28A-F illustrate a perspective view, a top view, a bottomview, a front view, a back view, and a side view, respectively, ofembodiments of a wound dressing including an obscuring layer and viewingwindows;

FIGS. 29A-B and 30 illustrate a top view of an embodiment of a wounddressing including a cross-shaped viewing window;

FIGS. 31A-B illustrate a top view of an embodiment of a wound dressingincluding slits in the wound dressing;

FIG. 32 illustrates an embodiment of a dressing comprising a viewingwindow in the shape of a trademarked brand name;

FIG. 33 illustrates a top view of an embodiment of a three-lobeconfiguration of a wound dressing and a dot pattern of viewing windows;

FIG. 34 illustrates a top view of an embodiment of a three-lobeconfiguration of a wound dressing and viewing windows in the shape of alogo;

FIG. 35 illustrates a top view of an embodiment of a three-lobe wounddressing;

FIG. 36 illustrates a top view of an embodiment of a three-lobe wounddressing with flared ends on each lobe;

FIG. 37A illustrates a top view of an embodiment of a four-lobe wounddressing with crescent shaped cut-outs as viewing windows;

FIG. 37B illustrates a top view of an embodiment of a four-lobe wounddressing with an array of dots at viewing windows;

FIG. 37C illustrates a top view of an embodiment of a four-lobe wounddressing with viewing windows;

FIG. 38 illustrates a perspective view of an embodiment of a four-lobewound dressing;

FIGS. 39A-B illustrate embodiments of white and colored fluidicconnectors, respectively;

FIGS. 40A-F illustrate a perspective view, a top view, a bottom view, afront view, a back view, and a side view, respectively, of an embodimentof an oval-shaped wound dressing;

FIGS. 41-48 illustrate embodiments of a wound dressing including anobscuring layer and viewing windows including an orifice viewing window;

FIGS. 49A-B illustrate embodiments of an oval-shaped wound dressingcomprising an obscuring layer and an orifice viewing window;

FIG. 50A illustrates an exploded view of an embodiment of a wounddressing;

FIG. 50B illustrates a cross sectional view of an embodiment of a wounddressing;

FIG. 51 illustrates an exploded view of an embodiment of a soft orflexible port for transmitting negative pressure to a wound dressing;

FIG. 52 illustrates an embodiment of a soft or flexible port attached toa wound dressing;

FIG. 53A illustrates a perspective view of a wound dressing;

FIG. 53B illustrates a bottom view of the wound dressing of FIG. 53A;and

FIG. 54 illustrates a CIE chromaticity scale.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Preferred embodiments disclosed herein relate to wound therapy for ahuman or animal body. Therefore, any reference to a wound herein canrefer to a wound on a human or animal body, and any reference to a bodyherein can refer to a human or animal body. The term “wound” as usedherein, in addition to having its broad ordinary meaning, includes anybody part of a patient that may be treated using negative pressure.Wounds include, but are not limited to, open wounds, incisions,lacerations, abrasions, contusions, burns, diabetic ulcers, pressureulcers, stoma, surgical wounds, trauma and venous ulcers or the like.Treatment of such wounds can be performed using negative pressure woundtherapy, wherein a reduced or negative pressure can be applied to thewound to facilitate and promote healing of the wound. It will also beappreciated that the negative pressure systems and methods as disclosedherein may be applied to other parts of the body, and are notnecessarily limited to treatment of wounds.

With reference initially to FIGS. 1A-B, treatment of a wound withnegative pressure in certain embodiments of the application uses a wounddressing 10 capable of absorbing and storing wound exudate inconjunction with a flexible suction adapter 12. In some embodiments, itmay be preferable for the wound site to be filled partially orcompletely with a wound packing material. This wound packing material isoptional, but may be desirable in certain wounds, for example deeperwounds. The wound packing material can be used in addition to the wounddressing 10. The wound packing material generally may comprise a porousand conformable material, for example foam (including reticulatedfoams), and gauze. Preferably, the wound packing material is sized orshaped to fit within the wound site so as to fill any empty spaces. Thewound dressing 10 may then be placed over the wound site and woundpacking material overlying the wound site. When a wound packing materialis used, once the wound dressing 10 is sealed over the wound site,negative pressure may be transmitted from a pump or other source ofnegative pressure through a flexible tubing 14 via the suction adapter12 to the wound dressing 10, through the wound packing material, andfinally to the wound site. This negative pressure draws wound exudateand other fluids or secretions away from the wound site.

The suction adapter 12 preferably comprises a head 11 that is in fluidiccommunication with the dressing 10 as will be described in furtherdetail below. The head 11 is illustrated here as being positioned at acorner of the dressing 10, but may also be positioned at any location onthe dressing. For example, some embodiments may provide for a centrallyor off-centered location not on an edge or corner of the dressing 10. Insome embodiments, the dressing 10 may comprise two or more suctionadapters 12, each comprising one or more heads 11, in fluidiccommunication therewith. In a preferred embodiment, the head 11 maymeasure 30 mm along its widest edge.

With reference now to FIG. 1B, certain embodiments of the wound dressing10 may comprise a plurality of layers. A wound contact layer 203 with anupper surface 202 and a lower surface 200 may be configured to carry anadhesive on its lower surface 200 for sealing the wound dressing 10 tothe wound site. A porous transmission layer 222 overlying the woundcontact layer 203 may comprise a 3D knitted or 3D fabric material, andthe transmission layer 222 may be configured to remain open uponapplication of negative pressure to the wound dressing. This facilitatesfluid flow 204 through the transmission layer 222, although thetransmission layer 222 does not retain a substantial amount of thefluid. An absorbent layer 220 overlying the transmission layer 222 maybe configured for absorbing wound exudate. A moisture vapor permeablecover layer 218 overlays the absorbent layer 220.

The wound contact layer 203 can be a polyurethane layer or polyethylenelayer or other flexible layer which is perforated, for example via a hotpin process, laser ablation process, ultrasound process or in some otherway or otherwise made permeable to liquid and gas. The perforations 104are through holes in the wound contact layer which enables fluid to flowthrough the layer. The wound contact layer 203 may help prevent tissueingrowth into the other material of the wound dressing 10. Theperforations are small enough to meet this requirement but still allowfluid through. For example, perforations formed as slits or holes havinga size ranging from 0.025 mm to 1.2 mm are considered small enough tohelp prevent tissue ingrowth into the wound dressing while allowingwound exudate to flow into the dressing. The wound contact layer 203 mayhelp hold the whole wound dressing together and helps to create an airtight seal around the absorbent pad in order to maintain negativepressure at the wound. The wound contact layer 230 may also act as acarrier for an optional lower and upper adhesive layer (not shown). Forexample, a lower pressure sensitive adhesive may be provided on theunderside surface 200 of the wound dressing whilst an upper pressuresensitive adhesive layer may be provided on the upper surface 202 of thewound contact layer. The pressure sensitive adhesive, which may be asilicone, hot melt, hydrocolloid or acrylic based adhesive or other suchadhesives, may be formed on both sides or optionally on a selected oneor none of the sides of the wound contact layer. When a lower pressuresensitive adhesive layer is utilized this may help adhere the wounddressing 10 to the skin around a wound site.

The layer 222 of porous material is located above the wound contactlayer 203. This porous layer, or transmission layer, 222 preferablyallows transmission of fluid including liquid and gas away from a woundsite into upper layers of the wound dressing. In particular, thetransmission layer 222 ensures that an open air channel can bemaintained to communicate negative pressure over the wound area evenwhen the absorbent layer 220 has absorbed substantial amounts ofexudates. The layer should remain open under the typical pressures thatwill be applied during negative pressure wound therapy as describedabove, so that the whole wound site sees an equalized negative pressure.The layer 222 is preferably formed of a material having a threedimensional structure. For example, a knitted or woven spacer fabric(for example Baltex 7970 weft knitted polyester) or a non-woven fabriccould be used. The transmission layer 222 may also comprise materialssuch foams, including open-cell foams such as polyethylene orpolyurethane foam, meshes, non-woven materials, and fluid channels.

In some embodiments, the transmission layer 222 comprises a 3D polyesterspacer fabric layer including a top layer (that is to say, a layerdistal from the wound-bed in use) which is a 84/144 textured polyester,and a bottom layer (that is to say, a layer which lies proximate to thewound bed in use) which is a 10 denier flat polyester and a third layerformed sandwiched between these two layers which is a region defined bya knitted polyester viscose, cellulose or the like monofilament fiber.Other materials and other linear mass densities of fiber could of coursebe used.

Whilst reference is made throughout this disclosure to a monofilamentfiber it will be appreciated that a multistrand alternative could ofcourse be utilized. The top spacer fabric thus has more filaments in ayarn used to form it than the number of filaments making up the yarnused to form the bottom spacer fabric layer.

This differential between filament counts in the spaced apart layershelps control moisture flow across the transmission layer. Particularly,by having a filament count greater in the top layer, that is to say, thetop layer is made from a yarn having more filaments than the yarn usedin the bottom layer, liquid tends to be wicked along the top layer morethan the bottom layer. In use, this differential tends to draw liquidaway from the wound bed and into a central region of the dressing wherethe absorbent layer 220 helps lock the liquid away or itself wicks theliquid onwards towards the cover layer where it can be transpired.

Preferably, to improve the liquid flow across the transmission layer 222(that is to say perpendicular to the channel region formed between thetop and bottom spacer layers, the 3D fabric may be treated with a drycleaning agent (such as, but not limited to, Perchloro Ethylene) to helpremove any manufacturing products such as mineral oils, fats and/orwaxes used previously which might interfere with the hydrophiliccapabilities of the transmission layer. In some embodiments, anadditional manufacturing step can subsequently be carried in which the3D spacer fabric is washed in a hydrophilic agent (such as, but notlimited to, Feran Ice 30 g/l available from the Rudolph Group). Thisprocess step helps ensure that the surface tension on the materials isso low that liquid such as water can enter the fabric as soon as itcontacts the 3D knit fabric. This also aids in controlling the flow ofthe liquid insult component of any exudates.

As stated previously, the layer 220 of absorbent material is providedabove the transmission layer 222. The absorbent material which may be afoam or non-woven natural or synthetic material and which may optionallyinclude or be super-absorbent material forms a reservoir for fluid,particularly liquid, removed from the wound site and draws those fluidstowards a cover layer 218. The material of the absorbent layer 220 alsoprevents liquid collected in the wound dressing from flowing in asloshing manner. The absorbent layer 220 also helps distribute fluidthroughout the layer via a wicking action so that fluid is drawn fromthe wound site and stored throughout the absorbent layer 220. This helpsprevent agglomeration in areas of the absorbent layer. The capacity ofthe absorbent material must be sufficient to manage the exudates flowrate of a wound when negative pressure is applied. Since in use theabsorbent layer 220 experiences negative pressures the material of theabsorbent layer 220 is chosen to absorb liquid under such circumstances.A number of materials exist that are able to absorb liquid when undernegative pressure, for example superabsorber material. The absorbentlayer 220 may typically be manufactured from ALLEVYN™ foam, Freudenberg114-224-4 and/or Chem-Posite™11C-450.

In some embodiments, the absorbent layer 220 is a layer of non-wovencellulose fibers having super-absorbent material in the form of dryparticles dispersed throughout. Use of the cellulose fibers introducesfast wicking elements which help quickly and evenly distribute liquidtaken up by the dressing. The juxtaposition of multiple strand-likefibers leads to strong capillary action in the fibrous pad which helpsdistribute liquid. In this way, the super-absorbent material isefficiently supplied with liquid. The wicking action also assists inbringing liquid into contact with the upper cover layer 218 to aidincrease transpiration rates of the dressing.

The wicking action also assists in delivering liquid downwards towardsthe wound bed when exudation slows or halts. This delivery process helpsmaintain the transmission layer and lower wound bed region in a moiststate which helps prevent crusting within the dressing (which could leadto blockage) and helps maintain an environment optimized for woundhealing.

In some embodiments, the absorbent layer 220 may be an air-laidmaterial. Heat fusible fibers may optionally be used to assist inholding the structure of the pad together. It will be appreciated thatrather than using super-absorbing particles or in addition to such use,super-absorbing fibers may be utilized according to certain embodimentsof the present invention. An example of a suitable material is theProduct Chem-Posite™ 11 C available from Emerging Technologies Inc.(ETi) in the USA.

Optionally, according to certain embodiments of the present invention,the absorbent layer 220 may include synthetic stable fibers and/orbi-component stable fibers and/or natural stable fibers and/orsuper-absorbent fibers. Fibers in the absorbent layer 220 may be securedtogether by latex bonding or thermal bonding or hydrogen bonding or acombination of any bonding technique or other securing mechanism. Insome embodiments, the absorbent layer 220 is formed by fibers whichoperate to lock super-absorbent particles within the absorbent layer220. This helps ensure that super-absorbent particles do not moveexternal to the absorbent layer 220 and towards an underlying wound bed.This is particularly helpful because when negative pressure is appliedthere is a tendency for the absorbent pad to collapse downwards and thisaction would push super-absorbent particle matter into a directiontowards the wound bed if they were not locked away by the fibrousstructure of the absorbent layer 220.

The absorbent layer 220 may comprise a layer of multiple fibers.Preferably, the fibers are strand-like and made from cellulose,polyester, viscose or the like. Preferably, dry absorbent particles aredistributed throughout the absorbent layer ready for use. In someembodiments, the absorbent layer 220 comprises a pad of cellulose fibersand a plurality of super absorbent particles. In additional embodiments,the absorbent layer is a non-woven layer of randomly orientatedcellulose fibers.

Super-absorber particles/fibers may be, for example, sodium polyacrylateor carboxymethylcellulose materials or the like or any material capableof absorbing many times its own weight in liquid. In some embodiments,the material can absorb more than five times its own weight of 0.9% W/Wsaline, etc. In some embodiments, the material can absorb more than 15times its own weight of 0.9% W/W saline, etc. In some embodiments, thematerial is capable of absorbing more than 20 times its own weight of0.9% W/W saline, etc. Preferably, the material is capable of absorbingmore than 30 times its own weight of 0.9% W/W saline, etc.

Preferably, the particles of superabsorber are very hydrophilic and grabthe fluid as it enters the dressing, swelling up on contact. Equilibriumis set up within the dressing core whereby moisture passes from thesuperabsorber into the dryer surrounding area and as it hits the topfilm the film switches and the fluid vapor starts to be transpired. Amoisture gradient is established within the dressing to continuallyremove fluid from the wound bed and ensure the dressing does not becomeheavy with exudate.

Turning now to the suction adapter 12, preferred embodiments comprise asealing surface 216, a bridge 211 with a proximal end and a distal end,and a filter 214. The sealing surface 216 may be configured for sealingthe suction adapter to the cover layer 218 of the wound dressing, andmay comprise an adhesive or weld. In some embodiments, the sealingsurface 216 may be placed over an orifice in the cover layer with spacerelements 215 configured to create a gap between the filter 214 and thetransmission layer 222. In other embodiments, the sealing surface 216may be positioned over an orifice in the cover layer 218 and an aperturein the absorbent layer 220, permitting the suction adapter 12 to provideair flow 206 through the transmission layer 222. In some embodiments,the bridge 211 may comprise a first fluid passage 212 in communicationwith a source of negative pressure, the first fluid passage 212comprising a porous material, such as a 3D knitted material, which maybe the same or different than the porous layer 222 described previously.The bridge 211 is preferably encapsulated by at least one flexible filmlayer 208, 210 having a proximal and distal end and configured tosurround the first fluid passage 212, the distal end of the flexiblefilm being connected the sealing surface 216. The filter 214 isconfigured to substantially prevent wound exudate from entering thebridge, and spacer elements 215 are configured to prevent the suctionadapter from contacting the transmission layer 222. These elements willbe described in greater detail below.

Some embodiments may further comprise an optional second fluid passagepositioned above the first fluid passage 212. For example, someembodiments may provide for an air leak may be disposed at the proximalend of the top layer that is configured to provide an air path into thefirst fluid passage 212 and dressing 10.

Preferably, the fluid passage 212 is constructed from a compliantmaterial that is flexible and that also permits fluid to pass through itif the spacer is kinked or folded over. Suitable materials for the fluidpassage 212 include without limitation foams, including open-cell foamssuch as polyethylene or polyurethane foam, meshes, 3D knitted fabrics,non-woven materials, and fluid channels. In some embodiments, the fluidpassage 212 may be constructed from materials similar to those describedabove in relation to the transmission layer 222. Advantageously, suchmaterials used in the fluid passage 212 not only permit greater patientcomfort, but may also provide greater kink resistance, such that thefluid passage 212 is still able to transfer fluid from the wound towardthe source of negative pressure while being kinked or bent.

In some embodiments, the fluid passage 212 may be comprised of a wickingfabric, for example a knitted or woven spacer fabric (such as a knittedpolyester 3D fabric, Baltex 7970®, or Gehring 879®) or a nonwovenfabric. These materials selected are preferably suited to channelingwound exudate away from the wound and for transmitting negative pressureand/or vented air to the wound site, and may also confer a degree ofkinking or occlusion resistance to the fluid passage 212. In someembodiments, the wicking fabric may have a three-dimensional structure,which in some cases may aid in wicking fluid or transmitting negativepressure. In certain embodiments, including wicking fabrics, thesematerials remain open and capable of communicating negative pressure toa wound area under the typical pressures used in negative pressuretherapy, for example between 40 to 150 mmHg. In some embodiments, thewicking fabric may comprise several layers of material stacked orlayered over each other, which may in some cases be useful in preventingthe fluid passage 212 from collapsing under the application of negativepressure. In other embodiments, the wicking fabric used in the fluidpassage 212 may be between 1.5 mm and 6 mm; more preferably, the wickingfabric may be between 3 mm and 6 mm thick, and may be comprised ofeither one or several individual layers of wicking fabric. In otherembodiments, the fluid passage 212 may be between 1.2-3 mm thick, andpreferably thicker than 1.5 mm. Some embodiments, for example a suctionadapter used with a dressing which retains liquid such as wound exudate,may employ hydrophobic layers in the fluid passage 212, and only gasesmay travel through the fluid passage 212. Additionally, and as describedpreviously, the materials used in the system are preferably conformableand soft, which may help to avoid pressure ulcers and othercomplications which may result from a wound treatment system beingpressed against the skin of a patient.

Preferably the absorbent layer 220 includes at least one area 246, suchas an edge or through hole, located so as to underlie the suctionadapter 12 where the absorbent layer 220 is removed or not provided. Itwill be appreciated that multiple openings could alternatively beutilized. As shown in FIG. 1A, this area 246 preferably underlies thepoint where the head 11 is in fluidic communication with the dressing.Additionally, should more than one suction adapter 12 be utilizedaccording to certain embodiments, one or multiple openings may be madein the super-absorbent layer 220 in registration with each respectivesuction adapter. Although not essential to certain embodiments of thepresent invention the use of through holes in the super-absorbent layer220 provide a fluid flow pathway which is particularly unhindered andthis is useful in certain circumstances.

Where an opening 246 is provided in the absorbent layer 220 thethickness of the layer itself will act as a stand-off separating anyoverlying layer from the upper surface (that is to say the surfacefacing away from a wound in use) of the transmission layer 222. Anadvantage of this is that the filter 214 is thus decoupled from thematerial of the transmission layer 222. This helps reduce the likelihoodthat the filter will be wetted out and thus will occlude and blockfurther operation.

Use of one or more through holes in the absorption layer 220 also hasthe advantage that during use if the absorbent layer contains a gelforming material, such as superabsorber, that material as it expands toabsorb liquid, does not form a barrier through which further liquidmovement and fluid movement in general cannot pass. In this way eachopening in the absorbent layer provides a fluid pathway between thetransmission layer directly to the wound facing surface of the filterand then onwards into the interior of the suction adapter.

The cover layer 218 extends across the width of the wound dressing, andis preferably gas impermeable, but moisture vapor permeable. The coverlayer 218, which may for example be a polyurethane film (for example,Elastollan SP9109) having a pressure sensitive adhesive on one side, ispreferably impermeable to gas and this layer thus operates to cover thewound and to seal a wound cavity over which the wound dressing isplaced. In this way an effective chamber is made between the cover layerand a wound site where a negative pressure can be established. The coverlayer 218 may for example be sealed to the wound contact layer 203 in aborder region 200 around the circumference of the dressing, ensuringthat no air is drawn in through the border area, for example viaadhesive or welding techniques. The cover layer 218 protects the woundfrom external bacterial contamination (bacterial barrier) and allowsliquid from wound exudates to be transferred through the layer andevaporated from the film outer surface. The cover layer 218 typicallycomprises two layers; a polyurethane film and an adhesive pattern spreadonto the film. The polyurethane film is moisture vapor permeable and maybe manufactured from a material that has an increased water transmissionrate when wet.

In some embodiments, the absorbent layer 220 may be of a greater areathan the transmission layer 222, such that the absorbent layer overlapsthe edges of the transmission layer 222, thereby ensuring that thetransmission layer does not contact the cover layer 218. This providesan outer channel of the absorbent layer 220 that is in direct contactwith the wound contact layer 203, which aids more rapid absorption ofexudates to the absorbent layer. Furthermore, this outer channel ensuresthat no liquid is able to pool around the circumference of the woundcavity, which may otherwise seep through the seal around the perimeterof the dressing leading to the formation of leaks.

In order to ensure that the air channel remains open when a vacuum isapplied to the wound cavity, the transmission layer 222 must besufficiently strong and non-compliant to resist the force due to thepressure differential. However, if this layer comes into contact withthe relatively delicate cover layer 218, it may cause the formation oftears, holes, or pin-hole openings in the cover layer 218 which allowair to leak into the wound cavity. This may be a particular problem whena switchable type polyurethane film is used that becomes weaker whenwet. The absorbent layer 220 is generally formed of a relatively soft,non-abrasive material compared to the material of the transmission layer222 and therefore does not cause the formation of pin-hole openings inthe cover layer. Thus by providing an absorbent layer 220 that is ofgreater area than the transmission layer 222 and that overlaps the edgesof the transmission layer 222, contact between the transmission layer222 and the cover layer 218 is prevented, avoiding the formation ofopenings in the cover layer 218.

The absorbent layer 220 is positioned in fluid contact with the coverlayer 218. As the absorbent layer 220 absorbs wound exudate, the exudateis drawn towards the cover layer 218, bringing the water component ofthe exudate into contact with the moisture vapor permeable cover layer.This water component is drawn into the cover layer itself and thenevaporates from the top surface of the dressing. In this way, the watercontent of the wound exudate can be transpired from the dressing,reducing the volume of the remaining wound exudate that is to beabsorbed by the absorbent layer 220, and increasing the time before thedressing becomes full and must be changed. This process of transpirationoccurs even when negative pressure has been applied to the wound cavity,and it has been found that the pressure difference across the coverlayer when a negative pressure is applied to the wound cavity hasnegligible impact on the moisture vapor transmission rate across thecover layer.

An orifice 245 is provided in the cover film 218 to allow a negativepressure to be applied to the dressing 10. A suction adapter 12 may besealed to the top of the cover film 218 over the orifice 245, andcommunicates negative pressure through the orifice 245. A length oftubing 14 may be coupled at a first end to the suction adapter 12 and ata second end to a pump unit (not shown) to allow fluids to be pumped outof the dressing. The suction adapter 12 may be adhered and sealed to thecover film 218 using an adhesive such as an acrylic, cyanoacrylate,epoxy, UV curable or hot melt adhesive. In some embodiments, the suctionadapter 12 may be separately attached to the cover film 218, while otherembodiments may provide for the dressing 10 to be provided with thesuction adapter 12 already attached to the cover film 218. The suctionadapter 12 may be formed from a soft polymer, for example apolyethylene, a polyvinyl chloride, a silicone or polyurethane having ahardness of 30 to 90 on the Shore A scale.

As discussed above, the area or through-hole 246 may be provided in theabsorbent layer 220 beneath the orifice 245 such that the orifice isconnected directly to the transmission layer 222. This allows thenegative pressure applied to the suction adapter 12 to be communicatedto the transmission layer 222 without passing through the absorbentlayer 220. This ensures that the negative pressure applied to the woundsite is not inhibited by the absorbent layer as it absorbs woundexudates. In other embodiments, no aperture may be provided in theabsorbent layer 220, or alternatively a plurality of aperturesunderlying the orifice 245 may be provided.

As shown in FIG. 1B, one embodiment of the wound dressing 10 comprisesan aperture 246 in the absorbent layer 10 situated underneath thesuction adapter 12. In use, for example when negative pressure isapplied to the dressing 10, a wound facing portion of the suctionadapter 12 may thus come into contact with the transmission layer 222,which can thus aid in transmitting negative pressure to the wound siteeven when the absorbent layer 220 is filled with wound fluids. Someembodiments may have the cover layer 218 be at least partly adhered tothe transmission layer 222. In some embodiments, the aperture 246 is atleast 1-2 mm larger than the diameter of the wound facing portion of thesuction adapter 12, or the orifice 245.

Preferably, the filter element 214 is impermeable to liquids, butpermeable to gases, and is provided to act as a liquid barrier and toensure that no liquids are able to escape from the wound dressing 10.The filter element 214 may also function as a bacterial barrier.Typically the pore size is 0.2 μm. Suitable materials for the filtermaterial of the filter element 214 include 0.2 micron Gore™ expandedPTFE from the MMT range, PALL Versapore™ 200R, and Donaldson™ TX6628.Larger pore sizes can also be used but these may require a secondaryfilter layer to ensure full bioburden containment. As wound fluidcontains lipids it is preferable, though not essential, to use anoleophobic filter membrane for example 1.0 micron MMT-332 prior to 0.2micron MMT-323. This prevents the lipids from blocking the hydrophobicfilter. The filter element can be attached or sealed to the port and/orthe cover film 218 over the orifice 245. For example, the filter element214 may be molded into the suction adapter 12, or may be adhered to oneor both of the top of the cover layer 218 and bottom of the suctionadapter 12 using an adhesive such as, but not limited to, a UV curedadhesive.

It will be understood that other types of material could be used for thefilter element 214. More generally a microporous membrane can be usedwhich is a thin, flat sheet of polymeric material, this containsbillions of microscopic pores. Depending upon the membrane chosen thesepores can range in size from 0.01 to more than 10 micrometers.Microporous membranes are available in both hydrophilic (waterfiltering) and hydrophobic (water repellent) forms. In some embodimentsof the invention, filter element 214 comprises a support layer and anacrylic co-polymer membrane formed on the support layer. Preferably thewound dressing 10 according to certain embodiments of the presentinvention uses microporous hydrophobic membranes (MHMs). Numerouspolymers may be employed to form MHMs. For example, the MHMs may beformed from one or more of PTFE, polypropylene, PVDF and acryliccopolymer. All of these optional polymers can be treated in order toobtain specific surface characteristics that can be both hydrophobic andoleophobic. As such these will repel liquids with low surface tensionssuch as multi-vitamin infusions, lipids, surfactants, oils and organicsolvents.

MHMs block liquids whilst allowing air to flow through the membranes.They are also highly efficient air filters eliminating potentiallyinfectious aerosols and particles. A single piece of MHM is well knownas an option to replace mechanical valves or vents. Incorporation ofMHMs can thus reduce product assembly costs improving profits andcosts/benefit ratio to a patient.

The filter element 214 may also include an odor absorbent material, forexample activated charcoal, carbon fiber cloth or Vitec Carbotec-RTQ2003073 foam, or the like. For example, an odor absorbent material mayform a layer of the filter element 214 or may be sandwiched betweenmicroporous hydrophobic membranes within the filter element. The filterelement 214 thus enables gas to be exhausted through the orifice 245.Liquid, particulates and pathogens however are contained in thedressing.

The wound dressing 10 may comprise spacer elements 215 in conjunctionwith the suction adapter 12 and the filter 214. With the addition ofsuch spacer elements 215 the suction adapter 12 and filter 214 may besupported out of direct contact with the absorbent layer 220 and/or thetransmission layer 222. The absorbent layer 220 may also act as anadditional spacer element to keep the filter 214 from contacting thetransmission layer 222. Accordingly, with such a configuration contactof the filter 214 with the transmission layer 222 and wound fluidsduring use may thus be minimized.

In particular for embodiments with a single suction adapter 12 andthrough hole 246, it may be preferable for the suction adapter 12 andthrough hole 246 to be located in an off-center position as illustratedin FIGS. 1A-B. Such a location may permit the dressing 10 to bepositioned onto a patient such that the suction adapter 12 is raised inrelation to the remainder of the dressing 10. So positioned, the suctionadapter 12 and the filter 214 may be less likely to come into contactwith wound fluids that could prematurely occlude the filter 214 so as toimpair the transmission of negative pressure to the wound site.

FIG. 2 illustrates an embodiment of a negative pressure wound treatmentsystem 5501 employing a wound dressing 5500 in conjunction with aflexible suction adapter 5512. The wound dressing 5500 may be similar tothe dressings illustrated in FIGS. 1A-B. Here, the flexible suctionadapter 5512 may comprise a bridge 5502 having a proximal end 5503 and adistal end 5505 and an applicator 5504 at the distal end 5505 of thebridge 5502. A connector 5504 is preferably disposed at the proximal end5503 of the bridge 5502. A cap 5536 may be provided with the system 5501(and can in some cases, as illustrated, be attached to the connector5504). The cap 5536 can be useful in preventing fluids from leaking outof the proximal end 5503. The system 5501 may include a source ofnegative pressure such as a pump or negative pressure unit 5534 capableof supplying negative pressure. The pump also preferably comprises acanister or other container for the storage of wound exudates and otherfluids that may be removed from the wound. In some embodiments, thispump 5534 can be a PICO™ pump, as sold by Smith & Nephew. The pump 5534may be connected to the connector 5504 via a tube 5540. In use, thedressing 5500 is placed over a suitably-prepared wound, which may insome cases be filled with a wound packing material such as foam orgauze. Subsequently, with the pump 5534 connected via the tube 5540 tothe connector 5504, the pump is activated, thereby supplying negativepressure to the wound. Application of negative pressure may be applieduntil a desired level of healing of the wound 5530 is achieved.

FIGS. 3A-C illustrate various embodiments of the head 11 of the suctionadapter 12. Preferably, the suction adapter 12 illustrated in FIGS. 1A-Cis enlarged at the distal end to be placed over the orifice in the coverlayer 218 and the aperture in the absorbent layer 220, and may form a“teardrop” or other enlarged shape. FIG. 3A illustrates a suctionadapter 12 with a substantially triangular head 11. FIG. 3B illustratesa suction adapter 12 with a substantially pentagonal head 11. FIG. 3Aillustrates a suction adapter 12 with a substantially circular head 11.

FIGS. 4A-D illustrate the use of an embodiment of a negative pressuretherapy wound treatment system being used to treat a wound site on apatient. FIG. 4A shows a wound site 490 being cleaned and prepared fortreatment. Here, the healthy skin surrounding the wound site 490 ispreferably cleaned and excess hair removed or shaved. The wound site 490may also be irrigated with sterile saline solution if necessary.Optionally, a skin protectant may be applied to the skin surrounding thewound site 490. If necessary, a wound packing material, such as foam orgauze, may be placed in the wound site 490. This may be preferable ifthe wound site 490 is a deeper wound.

After the skin surrounding the wound site 490 is dry, and with referencenow to FIG. 4B, the wound dressing 400 may be positioned and placed overthe wound site 490. The wound dressing 400 may be similar to the wounddressing 10 described above in relation to FIGS. 1A-B. Preferably, thewound dressing 400 is placed with the wound contact layer 203(illustrated in FIGS. 1A-B) over and/or in contact with the wound site490. In some embodiments, an adhesive layer is provided on the lowersurface 200 of the wound contact layer 203, which may in some cases beprotected by an optional release layer to be removed prior to placementof the wound dressing 400 over the wound site 490. Preferably, thedressing 400 is positioned such that the suction adapter 12 is in araised position with respect to the remainder of the dressing 400 so asto avoid fluid pooling around the port. In some embodiments, thedressing 400 is positioned so that the suction adapter 12 is notdirectly overlying the wound, and is level with or at a higher pointthan the wound. To help ensure adequate sealing for TNP, the edges ofthe dressing 400 are preferably smoothed over to avoid creases or folds.

With reference now to FIG. 4C, the dressing 400 is connected to the pump420. The pump 420 is configured to apply negative pressure to the woundsite via the dressing 400, and typically through a conduit. In someembodiments, and as described above in FIG. 28, a connector may be usedto join the conduit from the dressing 400 to the pump 420. Upon theapplication of negative pressure with the pump 420, the dressing 400 mayin some embodiments partially collapse and present a wrinkled appearanceas a result of the evacuation of some or all of the air underneath thedressing 400. In some embodiments, the pump 420 may be configured todetect if any leaks are present in the dressing 400, such as at theinterface between the dressing 400 and the skin surrounding the woundsite 490. Should a leak be found, such leak is preferably remedied priorto continuing treatment.

Turning to FIG. 4D, additional fixation strips 495 may also be attachedaround the edges of the dressing 400. Such fixation strips 495 may beadvantageous in some situations so as to provide additional sealingagainst the skin of the patient surrounding the wound site 490. Forexample, the fixation strips 495 may provide additional sealing for whena patient is more mobile. In some cases, the fixation strips 495 may beused prior to activation of the pump 420, particularly if the dressing400 is placed over a difficult to reach or contoured area.

Treatment of the wound site 490 preferably continues until the wound hasreached a desired level of healing. In some embodiments, it may bedesirable to replace the dressing 400 after a certain time period haselapsed, or if the dressing is full of wound fluids. During suchchanges, the pump 420 may be kept, with just the dressing 400 beingchanged.

Further details of dressings that may be used with the suction adapters,fluidic connectors or ports described herein include, but are notlimited to, dressings described in Provisional Application Ser. No.61/785,054, filed Mar. 14, 2013, the entirety of which is herebyincorporated by reference and portions of which were included as anappendix in Application Ser. No. 61/785,927 and are now described belowin the section entitled “Other Negative Pressure Therapy Apparatuses,Dressings and Methods.” Similarly, further details of suction adapters,fluidic connectors and other apparatuses that may be used with thedressings and other wound treatment apparatuses described herein arealso described in Application Ser. No. 61/785,054, filed Mar. 14, 2013and are described below in the section entitled “Other Negative PressureTherapy Apparatuses, Dressings and Methods.”

FIGS. 5A-B illustrate an embodiment of a flexible port or fluidicconnector 500. FIG. 5C illustrates a perspective exploded view thefluidic connector 500 that may be used to connect a wound dressing to asource of negative pressure. The port 500 comprises a top layer 510, aspacer layer 520, a filter element 530, a bottom layer 540, and aconduit 550. The conduit optionally comprises a connector 560. Thedistal end of the port 500 (the end connectable to the dressing) isdepicted as having an enlarged circular shape, although it will beappreciated that any suitable shape may be used and that the distal endneed not be enlarged. For example, the distal end can have any of theshapes shown in FIGS. 3A-3C above. The distal end can also have theshape shown in FIGS. 39A and 39B, discussed below.

The bottom layer 540 may comprise an elongate bridge portion 544, anenlarged (e.g., rounded or circular) sealing portion 545, and an orifice541. In some embodiments a plurality of orifices may be provided in thebottom layer. Some embodiments of the rounded sealing portion 545 maycomprise a layer of adhesive, for example a pressure sensitive adhesive,on the lower surface for use in sealing the port 500 to a dressing. Forexample, the port may be sealed to a cover layer of the dressing. Theorifice 541 in the bottom layer 540 of the port 500 may be aligned withan orifice in the cover layer of the dressing in order to transmitnegative pressure through the dressing and into a wound site.

The top layer 515 may be substantially the same shape as the bottomlayer in that it comprises an elongate bridge 514 and an enlarged (e.g.,rounded or circular) portion 545. The top layer 515 and the bottom layer545 may be sealed together, for example by heat welding. In someembodiments, the bottom layer 545 may be substantially flat and the toplayer 515 may be slightly larger than the bottom layer 545 in order toaccommodate the height of the spacer layer 520 and seal to the bottomlayer 545. In other embodiments, the top layer 515 and bottom layer 3145may be substantially the same size, and the layers may be sealedtogether approximately at the middle of the height of the spacer layer520. In some embodiments, the elongate bridge portions 544, 514 may havea length of 10 cm (or about 10 cm) or more, more preferably a length of20 cm (or about 20 cm) or more and in some embodiments, may be about 69cm (or 27 cm) long. Some embodiments of the entire flexible port, from aproximalmost edge of the top and bottom layers to a distalmost edge ofthe top and bottom layers, may be between 20 cm and 80 cm (or about 20cm to about 80 cm) long, more preferably about 60 cm and 80 cm (orbetween about 60 cm and about 80 cm) long, for example about 70 cm long.In some embodiments, the elongate bridge portions may have a width ofbetween 1 cm and 4 cm (or between about 1 cm and about 4 cm), and in oneembodiment, is about 2.5 cm wide. The ratio of the length of theelongate bridge portions 544, 514 to their widths may in someembodiments exceed 6:1, and may more preferably exceed 8:1 or even 10:1.The diameter of the circular portion 545, 515 may be about 3.5 cm insome embodiments.

The bottom and top layers may comprise at least one layer of a flexiblefilm, and in some embodiments may be transparent. Some embodiments ofthe bottom layer 540 and top layer 515 may be polyurethane, and may beliquid impermeable.

The port 500 may comprise a spacer layer 520, such as the 3D fabricdiscussed above, positioned between the lower layer 540 and the toplayer 510. The spacer layer 520 may be made of any suitable material,for example material resistant to collapsing in at least one direction,thereby enabling effective transmission of negative pressuretherethrough. Instead of or in addition to the 3D fabric discussedabove, some embodiments of the spacer layer 520 may comprise a fabricconfigured for lateral wicking of fluid, which may comprise viscose,polyester, polypropylene, cellulose, or a combination of some or all ofthese, and the material may be needle-punched. Some embodiments of thespacer layer 520 may comprise polyethylene in the range of 40-160 gramsper square meter (gsm) (or about 40 to about 160 gsm), for example 80(or about 80) gsm. Such materials may be constructed so as to resistcompression under the levels of negative pressure commonly appliedduring negative pressure therapy.

The spacer layer 520 may comprise an elongate bridge portion 524, anenlarged (e.g., rounded or circular) portion 525, and may optionallyinclude a fold 521. In some embodiments, the elongate bridge portion mayhave dimensions in the same ranges as the bridge portions of the upperand lower layers described above though slightly smaller, and in oneembodiment is about 25.5 cm long and 1.5 cm wide. Similarly, thediameter of the circular portion 525 may be slightly smaller than thediameters of the enlarged ends 545, 515, and in one embodiment is about2 cm. Some embodiments of the spacer layer 520 may have adhesive on oneor both of its proximal and distal ends (e.g., one or more dabs ofadhesive) in order to secure the spacer layer 520 to the top layer 510and/or the bottom layer 540. Adhesive may also be provided along aportion or the entire length of the spacer layer. In other embodiments,the spacer layer 520 may be freely movable within the sealed chamber ofthe top and bottom layers.

The fold 521 of the spacer layer may make the end of the port 500 softerand therefore more comfortable for a patient, and may also help preventthe conduit 550 from blockage. The fold 521 may further protect the endof the conduit 550 from being occluded by the top or bottom layers. Thefold 521 may, in some embodiments, be between 1 cm and 3 cm (or betweenabout 1 cm and about 3 cm) long, and in one embodiment is 2 cm (or about2 cm) long. The spacer layer may be folded underneath itself, that istoward the bottom layer 540, and in other embodiments may be foldedupward toward the top layer 510. Other embodiments of the spacer layer520 may contain no fold. A slot or channel 522 may extendperpendicularly away from the proximal end of the fold 521, and theconduit 550 may rest in the slot or channel 522. In some embodiments theslot 522 may extend through one layer of the fold, and in others it mayextend through both layers of the fold. The slot 522 may, in someembodiments, be 1 cm (or about 1 cm) long. Some embodiments may insteademploy a circular or elliptical hole in the fold 521. The hole may faceproximally so that the conduit 550 may be inserted into the hole andrest between the folded layers of spacer fabric. In some embodiments,the conduit 550 may be adhered to the material of the fold 3521, whilein other embodiments it may not.

The port 500 may have a filter element 530 located adjacent the orifice541, and as illustrated is located between the lower layer 540 and thespacer layer 520. The filter element 530 is impermeable to liquids, butpermeable to gases. The filter element may be similar to the elementdescribed above with respect to FIG. 1B, and as illustrated may have around or disc shape. The filter element 530 can act as a liquid barrier,to substantially prevent or inhibit liquids from escaping from the wounddressing, as well as an odor barrier. The filter element 530 may alsofunction as a bacterial barrier. In some embodiments, the pore size ofthe filter element 530 can be approximately 0.2 μm. Suitable materialsfor the filter material of the filter element include 0.2 micron Gore™expanded PTFE from the MMT range, PALL Versapore™ 200R, and Donaldson™TX6628. The filter element 530 thus enables gas to be exhausted throughthe orifice. Liquid, particulates and pathogens however are contained inthe dressing. Larger pore sizes can also be used but these may require asecondary filter layer to ensure full bioburden containment. As woundfluid contains lipids it is preferable, though not essential, to use anoleophobic filter membrane for example 1.0 micron MMT-332 prior to 0.2micron MMT-323. This prevents the lipids from blocking the hydrophobicfilter. In some embodiments, the filter element 530 may be adhered toone or both of top surface of the bottom layer 540 and the bottomsurface of the spacer layer 520 using an adhesive such as, but notlimited to, a UV cured adhesive. In other embodiments, the filter 530may be welded to the inside of the spacer layer 520 and to the topsurface of the bottom layer 540. The filter may also be providedadjacent the orifice on a lower surface of the bottom layer 540. Otherpossible details regarding the filter are disclosed in U.S. Patent Pub.No. 2011/0282309 and incorporated by reference herein.

The proximal end of the port 500 may be connected to the distal end of aconduit 550. The conduit 550 may comprise one or more circular ribs 551.The ribs 551 may be formed in the conduit 550 by grooves in a moldduring the manufacturing of the conduit. During heat welding of theupper and lower layers 515, 545 melted material from those layers mayflow around the ribs 551, advantageously providing a stronger connectionbetween the conduit 550 and the layers. As a result, it may be moredifficult to dislodge the conduit 550 out from between the layers duringuse of the port 500.

The proximal end of the conduit 550 may be optionally attached to aconnector 560. The connector 560 may be used to connect the port 500 toa source of negative pressure, or in some embodiments to an extensionconduit which may in turn be connected to a source of negative pressure.As explained in more detail below with respect to FIGS. 8A and 8B, theproximal end of the conduit 550, which is inserted into the spacerfabric 520, may be shaped in such a way to reduce the possibility ofocclusion. For example, some embodiments may have a triangular portioncut out of the end of the conduit, and other embodiments may have aplurality of holes therethrough.

FIG. 6 illustrates an embodiment of a wound dressing 610 with a flexibleport 620 such as described above with respect to FIGS. 5A-C attached tothe dressing. The port 620 may be the port described above in FIGS.5A-C. The port 620 may comprise a conduit 630 and a connector 640 forconnecting the port to a source of negative pressure or to an extensionconduit. Although in this depiction the port 620 is connected over acircular window in the obscuring layer of the dressing 610, in otherembodiments the port 620 may be connected over a maltese cross in theobscuring layer. In some embodiments, the maltese cross may be of alarger diameter than the port 620 and may be at least partially viewableafter the port 620 is attached to the dressing 610. Further detailsregarding the dressing 610 and other dressings to which the port can beconnected are described in Provisional Application Ser. No. 61/785,054,filed Mar. 14, 2013, incorporated by reference herein and describedfurther below in the section entitled “Other Negative Pressure TherapyApparatuses, Dressings and Methods.”

FIG. 7A depicts a perspective view of a flexible port 700 of the samedesign as shown with respect to FIGS. 5A-C. The port 700 comprisesspacer fabric 710, wherein the proximal end of spacer fabric 710comprises a fold 720, at least one layer of flexible film 740, anenlarged rounded distal end 715, a conduit 760, and a connector 780. Thecomponents of port 700 may have similar properties to the components ofFIGS. 5A-C, described above.

FIG. 7B illustrates a close up view of an embodiment of the proximal endof the flexible port 700. The port 700 comprises spacer fabric 710inside a sealed chamber 770 between layers of flexible film 740. The endof the spacer fabric 710 comprises a fold 720. At the proximal end ofthe fold, there may be a hole 730 through the fabric for inserting theconduit 760. The conduit 760 may rest between the folded portions of thespacer fabric. The conduit 760 comprises a plurality of ribs 750, whichmay, as described above with respect to FIGS. 5A-C, act to secure theconduit 760 between the layers of flexible film 740.

FIG. 7C illustrates a close up view of the bottom of the distal end ofthe flexible port 700. The bottom of the port 700 comprises an orifice792 for transmitting negative pressure to a dressing to which the portmay be attached. The port 700 comprises a filter 790, which may havesimilar properties to the filters described above with respect to FIGS.1B and 5A-C. In some embodiments, the filter 790 may have a portion 795which is adhered to the flexible film 740 around the perimeter of theorifice 795, thereby substantially maintaining the seal of chamber 770.

FIGS. 8A and 8B illustrate embodiments of the distal end of a conduit800 which may be part of any of the port embodiments described above.The distal end may be shaped in such a way to reduce the possibility ofocclusion. For example, the embodiment of FIG. 8A may have a triangularportion 810 cut out of the end of the conduit, and other embodiments mayhave a plurality of holes therethrough.

FIGS. 9-16 depict various views of an ornamental design of oneembodiment of a flexible port as described herein. As will be evidentfrom the various embodiments described herein, functionally equivalentalternative designs of such a flexible port are available, and theconfiguration of the design illustrated in FIGS. 9-16 was at least inpart the result of aesthetic and ornamental considerations. In the caseof the illustrated full flexible port design, the solid lines indicatethe incorporation of the entire structure as part of one embodiment ofan ornamental design for the flexible port. In the case of a partialflexible port design, any number of the solid lines may instead bedepicted as broken lines to indicate that a component illustrated inbroken lines is not part of that embodiment of the ornamental design.

Other Negative Pressure Therapy Apparatuses, Dressings and Methods(Incorporated from U.S. Provisional Application No. 61/785,054, Portionsof which were Included as an Appendix in U.S. Provisional ApplicationNo. 61/785,927)

Moreover, some embodiments disclosed herein are directed to systems thatinclude negative pressure therapy apparatuses and dressings, and methodsfor operating such negative pressure therapy apparatuses for use withnegative pressure therapy dressings. In one embodiment, a woundtreatment apparatus for treatment of a wound site comprises: a wounddressing comprising: an absorbent layer configured to retain fluid, abacking layer above the absorbent layer, and an obscuring layerconfigured to at least partly visually obscure fluid within theabsorbent layer; and a fluidic connector configured to transmit negativepressure from a negative pressure source to the wound dressing for theapplication of topical negative pressure at the wound site.

In some embodiments, the obscuring layer is above or below the backinglayer. The obscuring layer may configured to at least partially visuallyobscure fluid contained within the absorbent layer. The obscuring layermay comprise at least one viewing window configured to allow a visualdetermination of the saturation level of the absorbent layer. The atleast one viewing window may comprise at least one aperture made throughthe obscuring layer. The at least one viewing window may comprise atleast one uncolored region of the obscuring layer. The viewing windowmay comprise an array of dots. The array of dots may be distributed in astraight line of dots, the straight line of dots being positioned on acenter line along a length of the absorbent layer. The straight line ofdots may comprise an array of three dots. The straight line of dots maycomprise an array of five dots. The straight line of dots may comprisean array of eight dots. The array of dots may be distributed in twostraight lines of dots, the two straight lines of dots positioned to bean equal distance from a center line along a length of the absorbentlayer, the two straight lines of dots having an equal number of dots.The two straight lines of dots may comprise an array of three dots. Thetwo straight lines of dots may comprise an array of five dots. The arrayof dots may be distributed regularly over the obscuring layer to enableassessment of wound exudate spread. The viewing window may be selectedfrom the group consisting of a graphical element or a typographicalelement. The obscuring layer may comprise an auxiliary compound, whereinthe auxiliary compound may comprise activated charcoal configured toabsorb odors and configured to color or tint the obscuring layer. Thefluidic connector may comprise an obscuring element configured tosubstantially visually obscure wound exudate.

Some embodiments may further comprise an acquisition distribution layerbetween the wound contact layer and the absorbent material. Theabsorbent layer may comprise cellulose fibers and between 40% and 80%(or between about 40% and about 80%) superabsorbent particles. Theobscuring layer, in a dry state, may be configured to yield a CIE yvalue of 0.4 or less and a CIE x value of 0.5 or less on a CIE x, ychromaticity diagram. The obscuring layer, in a dry state, may have acolor of Bg, gB, B, pB, bP, P, rP, pPk, RP, O, rO, or yO on a CIE x, ychromaticity diagram.

In some embodiments, the wound dressing further comprises an orifice inthe backing layer, the orifice configured to communicate negativepressure to the wound site. The orifice may comprise at least oneorifice viewing window configured to be positioned adjacent to theorifice in the backing layer, the orifice viewing window configured toallow a visual determination of the saturation level of the absorbentlayer adjacent to the orifice. The orifice viewing window may becross-shaped. The wound dressing may comprise a first lengthcorresponding to a first edge of a wound dressing and a first widthcorresponding to a second edge of the wound dressing, a first x axisruns along the first width and a first y axis runs along the firstlength, wherein the first x axis and the first y axis are in aperpendicular alignment. The viewing window may comprise a first arm anda second arm, the first arm of the viewing window define a second lengthand the second arm defines a second width, a second x axis runs alongthe second width and a second y axis runs along the second length,wherein the second x axis and the second y axis are in a perpendicularalignment. The second x axis and second y axis of the viewing window isoffset from the first x axis and the first y axis of the absorbentlayer. The second x axis and second y axis of the viewing window may bealigned with the first x axis and the first y axis of the absorbentlayer. The cross-shaped transparent layer may comprise flared ends. Thefluidic connector may be configured to transmit air. The fluidicconnector may comprise a filter, the filter configured to block fluidtransport past itself. The fluidic connector may comprise a secondaryair leak channel, the secondary air leak channel configured to allow aflow of ambient air to the wound site. The secondary air leak channelmay comprise a filter. The fluidic connector may comprise a soft fluidicconnector. The soft fluidic connector may comprise a three dimensionalfabric. In some embodiments, the three dimensional fabric is configuredto transmit therapeutic levels of negative pressure while an externalpressure up to 2 kg/cm² is applied thereto. The soft fluidic connectormay be configured to be connected to a tube in fluid communication withthe vacuum source. The soft fluidic connector may be configured to beconnected directly to the vacuum source. The soft fluidic connector maycomprise an enlarged distal end, the enlarged distal end configured tobe connected to the wound dressing. The apparatus may further comprise atube connected to the fluidic connector. The apparatus may furthercomprise a pump in fluid communication with the fluidic connector. Insome embodiments, the absorbent layer comprises two or more lobes.

In another embodiment, a wound treatment apparatus for treatment of awound site comprises: a wound dressing configured to be positioned overa wound site, the wound dressing comprising: a backing layer having anupper surface and a lower surface and defining a perimeter configured tobe positioned over skin surrounding the wound site, the backing layerincluding an opening; a wound contact layer adhered to the lower surfaceof the backing layer, the wound contact layer comprising an adhesive ona lower surface thereof; an absorbent material positioned between thebacking layer and the wound contact layer, wherein the absorbentmaterial comprises a vertical hole positioned below the opening in thebacking layer; an obscuring layer positioned at least partially over theabsorbent material, wherein the obscuring layer comprises a verticalhole positioned between the opening in the backing layer and thevertical hole in the absorbent material; one or more viewing windowsextending through the obscuring layer configured to allow visualizationof wound exudate in the absorbent material; and a port positioned overthe opening in the backing layer configured to transmit negativepressure through the port for the application of topical negativepressure at the wound site.

In some embodiments, the backing layer is transparent or translucent.The backing layer may define a perimeter with a rectangular or a squareshape. The wound contact layer may be adhered to the lower surface ofthe backing layer along the perimeter of the backing layer. The hole inthe obscuring layer may have a different diameter than the hole in theabsorbent material or the opening in the backing layer. The one or moreviewing windows may be arranged in a repeating pattern across theobscuring layer. The one or more viewing windows may have a circularshape.

Some embodiments may further comprise an acquisition distribution layerbetween the wound contact layer and the absorbent material. Theabsorbent layer may comprise cellulose fibers and between 40% and 80%(or between about 40% and about 80%) superabsorbent particles. Theobscuring layer, in a dry state, may be configured to yield a color ofBg, gB, B, pB, bP, P, rP, pPk, RP, O, rO, or yO on the CIE x, ychromaticity diagram.

Some embodiments further comprise a transmission layer between theabsorbent material and the wound contact layer. In some embodiments, theapparatus further comprises a hydrophobic filter positioned in or belowthe port. The absorbent material may have a longitudinal length and atransverse width, wherein the length is greater than the width, andwherein the width of the absorbent material narrows in a central portionalong the longitudinal length of the absorbent material. The obscuringlayer may have substantially the same perimeter shape as the absorbentmaterial. The apparatus may further comprise a pump.

In another embodiment, a wound treatment apparatus for treatment of awound site comprises: a wound dressing configured to be conformable to anonplanar wound comprising: an absorbent layer comprising a contouredshape, the contoured shape comprising a substantially rectangular bodywith a waisted portion, and a backing layer above the absorbent layer;and a fluidic connector configured to transmit negative pressure from anegative pressure source to the wound dressing for the application oftopical negative pressure at a wound site.

Some embodiments may further comprise a wound contact layer. The backinglayer may be rectangular. In some embodiments, the negative pressuresource is a pump.

In some embodiments, the wound dressing has a longer axis and a shorteraxis, and wherein the waisted portion configured to be on the longeraxis. The apparatus may further comprise an obscuring layer configuredto at least partly visually obscure fluid within the absorbent layer.The obscuring layer may comprise at least one viewing window configuredto allow a visual determination of the saturation level of the absorbentlayer. The viewing window may comprise an array of dots. The fluidicconnector may be located along a side or corner of the rectangular body.

Some embodiments may further comprise an acquisition distribution layerbetween the wound contact layer and the absorbent material. Theabsorbent layer may comprise cellulose fibers and 40%-80% (or about 40%to about 80%) superabsorbent particles. The obscuring layer, in a drystate, may be configured to yield a color of Bg, gB, B, pB, bP, P, rP,pPk, RP, O, rO, or yO on the CIE x, y chromaticity diagram.

In yet another embodiment, an apparatus for dressing a wound for theapplication of topical negative pressure at a wound site, comprises: anabsorbent layer having one or more slits extending at least partiallyacross the width of the absorbent layer; and a backing layer above theabsorbent layer, the backing layer having an orifice for communicatingnegative pressure to the wound site, wherein the orifice is positionedover a portion of the absorbent layer having no slits.

In some embodiments, the one or more slits comprise one or moreconcentric arcs.

In another embodiment, a wound treatment apparatus comprises: a wounddressing configured to be conformable to a nonplanar wound comprising:an absorbent layer above the contact layer, the absorbent layercomprising a contoured shape, the contoured shape comprising two or morelobes, and a backing layer above the absorbent layer.

In some embodiments, the wound treatment apparatus comprises a pump. Thewound dressing may comprise a fluidic connector configured to transmitnegative pressure from a pump to the wound dressing for the applicationof topical negative pressure at a wound site. The wound dressing mayalso comprise a wound-facing contact layer. The contoured shape maycomprise three lobes. The contoured shape may comprise four lobes. Thetwo or more lobes may comprise rounded projections. The apparatus maycomprise two or more lobes flared lobes. The contoured shape may beoval-shaped. The contoured shape may comprise six lobes. The apparatusmay further comprise an obscuring layer disposed so as to obscure theabsorbent layer. The apparatus may further comprise an obscuring layerconfigured to at least partly visually obscure fluid within theabsorbent layer. The obscuring layer may comprise at least one viewingwindow configured to allow a visual determination of the saturationlevel of the absorbent layer. The viewing window may comprise an arrayof dots.

In yet another embodiment, an apparatus for dressing a wound for theapplication of topical negative pressure at a wound site, comprises: awound contact layer; an acquisition distribution layer above thetransmission layer; an absorbent layer over the acquisition anddistribution layer, the absorbent layer comprising a matrix andsuperabsorbing particles within the matrix; and a backing layer abovethe absorbent layer.

Some embodiments of the apparatus may further comprise a transmissionlayer between the wound contact layer and the acquisition distributionlayer. The acquisition distribution layer may comprise viscose,polyester, polypropylene, cellulose, polyethylene or a combination ofsome or all of these materials. The absorbent layer may comprise between30% and 40% (or between about 30% and about 40%) cellulose matrix andbetween 60% and 70% (or between about 60% and about 70%) superabsorbingpolymers. The backing layer may be transparent or translucent.

Some embodiments may further comprise an obscuring layer between theabsorbent layer and the backing layer. There may be one or more viewingwindows in the obscuring layer. At least the obscuring layer may beshaped with a narrowed central portion along its length. The obscuringlayer may comprise two rows of three viewing windows, one row of threeviewing windows, one row of eight viewing windows, two rows of fiveviewing windows, or one row of five viewing windows. At least theobscuring layer may be shaped with a narrowed central portion along bothits width and its length. The obscuring layer may comprise a 3×3 arrayof viewing window or a quincunx array of viewing windows. In someembodiments, at least the obscuring layer may comprise a six-lobedshape. The absorbent layer and acquisition distribution layer may besubstantially the same shape as the obscuring layer. The obscuring layermay further comprise a cross or maltese cross shaped hole over which afluidic connector for transmitting negative pressure may be connected.The apparatus may further comprise a fluidic connector configured toconnect the backing layer to a source of negative pressure.

In yet another embodiment, an apparatus for dressing a wound for theapplication of topical negative pressure at a wound site, comprises: anabsorbent layer configured to retain fluid, a backing layer above theabsorbent layer, and an obscuring layer configured to at least partlyvisually obscure fluid within the absorbent layer, wherein the obscuringlayer, in a dry state, is configured to yield a color of Bg, gB, B, pB,bP, P, rP, pPk, RP, O, rO, or yO on the CIE x, y chromaticity diagram.

Some embodiments may further comprise one or more viewing windows in thebacking layer. At least the obscuring layer may be shaped with anarrowed central portion along its length. The obscuring layer maycomprise a 3×3 array of viewing window or a quincunx array of viewingwindows. In some embodiments, at least the obscuring layer may comprisea six-lobed shape. The absorbent layer and acquisition distributionlayer may be substantially the same shape as the obscuring layer. Theobscuring layer may further comprise a cross or maltese cross shapedhole over which a fluidic connector for transmitting negative pressuremay be connected. The apparatus may further comprise a fluidic connectorconfigured to connect the backing layer to a source of negativepressure.

FIG. 17 illustrates an embodiment of a TNP wound treatment system B100comprising a wound dressing B110 in combination with a pump B150. Asstated above, the wound dressing B110 can be any wound dressingembodiment disclosed herein including without limitation dressingembodiment or have any combination of features of any number of wounddressing embodiments disclosed herein. Here, the dressing B110 may beplaced over a wound as described previously, and a conduit B130 may thenbe connected to the port B120, although in some embodiments the dressingB101 may be provided with at least a portion of the conduit B130preattached to the port B120. Preferably, the dressing B110 is providedas a single article with all wound dressing elements (including the portB120) pre-attached and integrated into a single unit. The wound dressingB110 may then be connected, via the conduit B130, to a source ofnegative pressure such as the pump B150. The pump B150 can beminiaturized and portable, although larger conventional pumps may alsobe used with the dressing B110. In some embodiments, the pump B150 maybe attached or mounted onto or adjacent the dressing B110. A connectorB140 may also be provided so as to permit the conduit B130 leading tothe wound dressing B110 to be disconnected from the pump, which may beuseful for example during dressing changes.

FIGS. 18A-D illustrate the use of an embodiment of a TNP wound treatmentsystem being used to treat a wound site on a patient. FIG. 18A-shows awound site B200 being cleaned and prepared for treatment. Here, thehealthy skin surrounding the wound site B200 is preferably cleaned andexcess hair removed or shaved. The wound site B200 may also be irrigatedwith sterile saline solution if necessary. Optionally, a skin protectantmay be applied to the skin surrounding the wound site B200. Ifnecessary, a wound packing material, such as foam or gauze, may beplaced in the wound site B200. This may be preferable if the wound siteB200 is a deeper wound.

After the skin surrounding the wound site B200 is dry, and withreference now to FIG. 18B, the wound dressing B110 may be positioned andplaced over the wound site B200. Preferably, the wound dressing B110 isplaced with the wound contact layer B2102 over and/or in contact withthe wound site B200. In some embodiments, an adhesive layer is providedon the lower surface B2101 of the wound contact layer B2102, which mayin some cases be protected by an optional release layer to be removedprior to placement of the wound dressing B110 over the wound site B200.Preferably, the dressing B110 is positioned such that the port B2150 isin a raised position with respect to the remainder of the dressing B110so as to avoid fluid pooling around the port. In some embodiments, thedressing B110 is positioned so that the port B2150 is not directlyoverlying the wound, and is level with or at a higher point than thewound. To help ensure adequate sealing for TNP, the edges of thedressing B110 are preferably smoothed over to avoid creases or folds.

With reference now to FIG. 18C, the dressing B110 is connected to thepump B150. The pump B150 is configured to apply negative pressure to thewound site via the dressing B110, and typically through a conduit. Insome embodiments, and as described above in FIG. 17, a connector may beused to join the conduit from the dressing B110 to the pump B150. Uponthe application of negative pressure with the pump B150, the dressingB110 may, in some embodiments, partially collapse and present a wrinkledappearance as a result of the evacuation of some or all of the airunderneath the dressing B110. In some embodiments, the pump B150 may beconfigured to detect if any leaks are present in the dressing B110, suchas at the interface between the dressing B110 and the skin surroundingthe wound site B200. Should a leak be found, such leak is preferablyremedied prior to continuing treatment.

Turning to FIG. 18D, additional fixation strips B210 may also beattached around the edges of the dressing B110. Such fixation stripsB210 may be advantageous in some situations so as to provide additionalsealing against the skin of the patient surrounding the wound site B200.For example, the fixation strips B210 may provide additional sealing forwhen a patient is more mobile. In some cases, the fixation strips B210may be used prior to activation of the pump B150, particularly if thedressing B110 is placed over a difficult to reach or contoured area.

Treatment of the wound site B200 preferably continues until the woundhas reached a desired level of healing. In some embodiments, it may bedesirable to replace the dressing B110 after a certain time period haselapsed, or if the dressing is full of wound fluids. During suchchanges, the pump B150 may be kept, with just the dressing B110 beingchanged.

FIGS. 19A-C illustrate cross-sections through a wound dressing B2100similar to the wound dressing of FIG. 17 according to an embodiment ofthe disclosure. A view from above the wound dressing B2100 isillustrated in FIG. 17 with the line A-A indicating the location of thecross-section shown in FIGS. 19A and 19B. The wound dressing B2100,which can alternatively be any wound dressing embodiment disclosedherein including without limitation wound dressing B110 or anycombination of features of any number of wound dressing embodimentsdisclosed herein, can be located over a wound site to be treated. Thedressing B2100 may be placed to as to form a sealed cavity over thewound site. In a preferred embodiment, the dressing B2100 comprises abacking layer B2140 attached to a wound contact layer B2102, both ofwhich are described in greater detail below. These two layers B2140,B2102 are preferably joined or sealed together so as to define aninterior space or chamber. This interior space or chamber may compriseadditional structures that may be adapted to distribute or transmitnegative pressure, store wound exudate and other fluids removed from thewound, and other functions which will be explained in greater detailbelow. Examples of such structures, described below, include atransmission layer B2105 and an absorbent layer B2110.

As illustrated in FIGS. 19A-C, a lower surface B2101 of the wounddressing B2100 may be provided with an optional wound contact layerB2102. The wound contact layer B2102 can be a polyurethane layer orpolyethylene layer or other flexible layer which is perforated, forexample via a hot pin process, laser ablation process, ultrasoundprocess or in some other way or otherwise made permeable to liquid andgas. The wound contact layer B2102 has a lower surface B2101 and anupper surface B2103. The perforations B2104 preferably comprise throughholes in the wound contact layer B2102 which enable fluid to flowthrough the layer B2102. The wound contact layer B2102 helps preventtissue ingrowth into the other material of the wound dressing.Preferably, the perforations are small enough to meet this requirementwhile still allowing fluid to flow therethrough. For example,perforations formed as slits or holes having a size ranging from 0.025mm to 1.2 mm are considered small enough to help prevent tissue ingrowthinto the wound dressing while allowing wound exudate to flow into thedressing. In some configurations, the wound contact layer B2102 may helpmaintain the integrity of the entire dressing B2100 while also creatingan air tight seal around the absorbent pad in order to maintain negativepressure at the wound.

Some embodiments of the wound contact layer B2102 may also act as acarrier for an optional lower and upper adhesive layer (not shown). Forexample, a lower pressure sensitive adhesive may be provided on thelower surface B2101 of the wound dressing B2100 whilst an upper pressuresensitive adhesive layer may be provided on the upper surface B2103 ofthe wound contact layer. The pressure sensitive adhesive, which may be asilicone, hot melt, hydrocolloid or acrylic based adhesive or other suchadhesives, may be formed on both sides or optionally on a selected oneor none of the sides of the wound contact layer. When a lower pressuresensitive adhesive layer is utilized may be helpful to adhere the wounddressing B2100 to the skin around a wound site. In some embodiments, thewound contact layer may comprise perforated polyurethane film. The lowersurface of the film may be provided with a silicone pressure sensitiveadhesive and the upper surface may be provided with an acrylic pressuresensitive adhesive, which may help the dressing maintain its integrity.In some embodiments, a polyurethane film layer may be provided with anadhesive layer on both its upper surface and lower surface, and allthree layers may be perforated together.

A layer B2105 of porous material can be located above the wound contactlayer B2102. This porous layer, or transmission layer, B2105 allowstransmission of fluid including liquid and gas away from a wound siteinto upper layers of the wound dressing. In particular, the transmissionlayer B2105 preferably ensures that an open air channel can bemaintained to communicate negative pressure over the wound area evenwhen the absorbent layer has absorbed substantial amounts of exudates.The layer B2105 should preferably remain open under the typicalpressures that will be applied during negative pressure wound therapy asdescribed above, so that the whole wound site sees an equalized negativepressure. The layer B2105 may be formed of a material having a threedimensional structure. For example, a knitted or woven spacer fabric(for example Baltex 7970 weft knitted polyester) or a non-woven fabriccould be used.

A layer B2110 of absorbent material is provided above the transmissionlayer B2105. The absorbent material, which comprise a foam or non-wovennatural or synthetic material, and which may optionally comprise asuper-absorbent material, forms a reservoir for fluid, particularlyliquid, removed from the wound site. In some embodiments, the layerB2100 may also aid in drawing fluids towards the backing layer B2140.

With reference to FIGS. 19A-C, a masking or obscuring layer B2107 can bepositioned beneath at least a portion of the backing layer B2140. Insome embodiments, the obscuring layer B2107 can have any of the samefeatures, materials, or other details of any of the other embodiments ofthe obscuring layers disclosed herein, including but not limited tohaving any viewing windows or holes. Additionally, the obscuring layerB2107 can be positioned adjacent to the backing layer, or can bepositioned adjacent to any other dressing layer desired. In someembodiments, the obscuring layer B2107 can be adhered to or integrallyformed with the backing layer. Preferably, the obscuring layer B2107 isconfigured to have approximately the same size and shape as theabsorbent layer B2110 so as to overlay it. As such, in these embodimentsthe obscuring layer B2107 will be of a smaller area than the backinglayer B2140.

The material of the absorbent layer B2110 may also prevent liquidcollected in the wound dressing B2100 from flowing freely within thedressing, and preferably acts so as to contain any liquid collectedwithin the absorbent layer B2110. The absorbent layer B2110 also helpsdistribute fluid throughout the layer via a wicking action so that fluidis drawn from the wound site and stored throughout the absorbent layer.This helps prevent agglomeration in areas of the absorbent layer. Thecapacity of the absorbent material must be sufficient to manage theexudates flow rate of a wound when negative pressure is applied. Sincein use the absorbent layer experiences negative pressures the materialof the absorbent layer is chosen to absorb liquid under suchcircumstances. A number of materials exist that are able to absorbliquid when under negative pressure, for example superabsorber material.The absorbent layer B2110 may typically be manufactured from ALLEVYN™foam, Freudenberg 114-224-4 and/or Chem-Posite™11C-450. In someembodiments, the absorbent layer B2110 may comprise a compositecomprising superabsorbent powder, fibrous material such as cellulose,and bonding fibers. In a preferred embodiment, the composite is anairlaid, thermally-bonded composite.

An orifice B2145 is preferably provided in the backing layer B2140 toallow a negative pressure to be applied to the dressing B2100. A suctionport B2150 is preferably attached or sealed to the top of the backinglayer B2140 over an orifice B2145 made into the dressing B2100, andcommunicates negative pressure through the orifice B2145. A length oftubing B2220 may be coupled at a first end to the suction port B2150 andat a second end to a pump unit (not shown) to allow fluids to be pumpedout of the dressing. The port may be adhered and sealed to the backinglayer B2140 using an adhesive such as an acrylic, cyanoacrylate, epoxy,UV curable or hot melt adhesive. The port B2150 is formed from a softpolymer, for example a polyethylene, a polyvinyl chloride, a silicone orpolyurethane having a hardness of 30 to 90 on the Shore A scale. In someembodiments, the port B2150 may be made from a soft or conformablematerial, for example using the embodiments described below in FIGS.39A-B.

Preferably the absorbent layer B2110 and the obscuring layer B2107include at least one through hole B2146 located so as to underlie theport B2150. The through hole B2146, while illustrated here as beinglarger than the hole through the obscuring layer B2107 and backing layerB2140, may in some embodiments be bigger or smaller than either. Ofcourse, the respective holes through these various layers B2107, B2140,and B2110 may be of different sizes with respect to each other. Asillustrated in FIGS. 19A-C a single through hole can be used to producean opening underlying the port B2150. It will be appreciated thatmultiple openings could alternatively be utilized. Additionally shouldmore than one port be utilized according to certain embodiments of thepresent disclosure one or multiple openings may be made in the absorbentlayer and the obscuring layer in registration with each respective port.Although not essential to certain embodiments of the present disclosurethe use of through holes in the super-absorbent layer may provide afluid flow pathway which remains unblocked in particular when theabsorbent layer B2100 is near saturation.

The aperture or through-hole B2146 is preferably provided in theabsorbent layer B2110 and the obscuring layer B2107 beneath the orificeB2145 such that the orifice is connected directly to the transmissionlayer B2105. This allows the negative pressure applied to the port B2150to be communicated to the transmission layer B2105 without passingthrough the absorbent layer B2110. This ensures that the negativepressure applied to the wound site is not inhibited by the absorbentlayer as it absorbs wound exudates. In other embodiments, no aperturemay be provided in the absorbent layer B2110 and/or the obscuring layerB2107, or alternatively a plurality of apertures underlying the orificeB2145 may be provided.

The backing layer B2140 is preferably gas impermeable, but moisturevapor permeable, and can extend across the width of the wound dressingB2100. The backing layer B2140, which may for example be a polyurethanefilm (for example, Elastollan SP9109) having a pressure sensitiveadhesive on one side, is impermeable to gas and this layer thus operatesto cover the wound and to seal a wound cavity over which the wounddressing is placed. In this way an effective chamber is made between thebacking layer B2140 and a wound site where a negative pressure can beestablished. The backing layer B2140 is preferably sealed to the woundcontact layer B2102 in a border region B2200 around the circumference ofthe dressing, ensuring that no air is drawn in through the border area,for example via adhesive or welding techniques. The backing layer B2140protects the wound from external bacterial contamination (bacterialbarrier) and allows liquid from wound exudates to be transferred throughthe layer and evaporated from the film outer surface. The backing layerB2140 preferably comprises two layers; a polyurethane film and anadhesive pattern spread onto the film. The polyurethane film ispreferably moisture vapor permeable and may be manufactured from amaterial that has an increased water transmission rate when wet.

The absorbent layer B2110 may be of a greater area than the transmissionlayer B2105, such that the absorbent layer overlaps the edges of thetransmission layer B2105, thereby ensuring that the transmission layerdoes not contact the backing layer B2140. This provides an outer channelB2115 of the absorbent layer B2110 that is in direct contact with thewound contact layer B2102, which aids more rapid absorption of exudatesto the absorbent layer. Furthermore, this outer channel B2115 ensuresthat no liquid is able to pool around the circumference of the woundcavity, which may otherwise seep through the seal around the perimeterof the dressing leading to the formation of leaks.

As shown in FIG. 19A, one embodiment of the wound dressing B2100comprises an aperture B2146 in the absorbent layer B2110 situatedunderneath the port B2150. In use, for example when negative pressure isapplied to the dressing B2100, a wound facing portion of the port B150may thus come into contact with the transmission layer B2105, which canthus aid in transmitting negative pressure to the wound site even whenthe absorbent layer B2110 is filled with wound fluids. Some embodimentsmay have the backing layer B2140 be at least partly adhered to thetransmission layer B2105. In some embodiments, the aperture B2146 is atleast 1-2 mm larger than the diameter of the wound facing portion of theport B2150, or the orifice B2145.

A filter element B2130 that is impermeable to liquids, but permeable togases is provided to act as a liquid barrier, and to ensure that noliquids are able to escape from the wound dressing. The filter elementmay also function as a bacterial barrier. Typically the pore size is 0.2μm. Suitable materials for the filter material of the filter elementB2130 include 0.2 micron Gore™ expanded PTFE from the MMT range, PALLVersapore™ B200R, and Donaldson™ TX6628. Larger pore sizes can also beused but these may require a secondary filter layer to ensure fullbioburden containment. As wound fluid contains lipids it is preferable,though not essential, to use an oleophobic filter membrane for example1.0 micron MMT-332 prior to 0.2 micron MMT-323. This prevents the lipidsfrom blocking the hydrophobic filter. The filter element can be attachedor sealed to the port and/or the backing layer B2140 over the orificeB2145. For example, the filter element B2130 may be molded into the portB2150, or may be adhered to both the top of the backing layer B2140 andbottom of the port B2150 using an adhesive such as, but not limited to,a UV cured adhesive.

In FIG. 19B, an embodiment of the wound dressing B2100 is illustratedwhich comprises spacer elements B2152, B2153 in conjunction with theport B2150 and the filter B2130. With the addition of such spacerelements B2152, B2153, the port B2150 and filter B2130 may be supportedout of direct contact with the absorbent layer B2110 and/or thetransmission layer B2105. The absorbent layer B2110 may also act as anadditional spacer element to keep the filter B2130 from contacting thetransmission layer B2105. Accordingly, with such a configuration contactof the filter B2130 with the transmission layer B2105 and wound fluidsduring use may thus be minimized. As contrasted with the embodimentillustrated in FIG. 19A, the aperture B2146 through the absorbent layerB2110 and the obscuring layer B2107 may not necessarily need to be aslarge or larger than the port B2150, and would thus only need to belarge enough such that an air path can be maintained from the port tothe transmission layer B2105 when the absorbent layer B2110 is saturatedwith wound fluids.

With reference now to FIG. 19C, which shares many of the elementsillustrated in FIGS. 19A-C, the embodiment illustrated here comprisesthe backing layer B2140, masking layer B2107, and absorbent layer B2110,all of which have a cut or opening made therethrough which communicatedirectly to the transmission layer B2105 so as to form the orificeB2145. The suction port B2150 is preferably situated above it andcommunicates with the orifice B2145.

In particular for embodiments with a single port B2150 and through hole,it may be preferable for the port B2150 and through hole to be locatedin an off-center position as illustrated in FIGS. 19A-C and in FIG. 17.Such a location may permit the dressing B2100 to be positioned onto apatient such that the port B2150 is raised in relation to the remainderof the dressing B2100. So positioned, the port B2150 and the filterB2130 may be less likely to come into contact with wound fluids thatcould prematurely occlude the filter B2130 so as to impair thetransmission of negative pressure to the wound site.

FIGS. 20A-C illustrate embodiments of wound dressings B300 similar tothe embodiments described above and provided with a narrowed centralportion in various lengths and widths. FIG. 20A illustrates anembodiment of a wound dressing B300 with a narrowed central portion or awaisted middle portion. The wound dressing B300 has a backing layerB301. The backing layer B301 can have a rectangular or square shapedperimeter and can be a transparent or translucent material. The backinglayer B301 can have a lower surface B305 and an upper surface B306. Thelower surface of the backing layer B301 can be configured to be placedon the skin surface surrounding the wound site as discussed previouslywith reference to FIGS. 19A-C. Additionally, the lower surface B305 canhave a wound contact layer. The wound contact layer can have all thefeatures and embodiments described herein, including without limitationwound dressing embodiments described in reference to FIGS. 19A-C. Thewound contact layer can be adhered to the perimeter of the lower surfaceB305 of the backing layer B301. The wound contact layer can comprise anadhesive or any other method of attachment that allows attachment of thewound dressing to the skin surface as previously described.

In some embodiments, the wound dressing B300 can have a port B304 offsetfrom the center of the dressing as described previously. The port B304can be a domed port or a soft fluidic connector (described in detailbelow). Although the port B304 can be placed in a central location onthe dressing, it is preferably offset from the center of the dressing toa particular side or edge. As such, the orientation of the port B304,when placed on the body, may thus permit the port B304 to be situated inan elevated position, thereby increasing the amount of time that thedressing B300 may be used before coming into contact with fluids.Although other orientations may be used, and may occur in practice(e.g., when the patient shifts positions), placing the port B304 at alower position may cause the filter proximate the port (not illustratedhere) to become saturated, which may cause the dressing to need changingeven though there may still remain some absorptive capacity within theabsorbent layer. Preferably, the port B304 has an orifice for theconnection of a tube or conduit thereto; this orifice may be angled awayfrom the center of the dressing B300 so as to permit the tube or conduitto extend away from the dressing B300. In some preferred embodiments,the port B304 comprises an orifice that permits the tube or conduitinserted therein to be approximately parallel to the top surface of thebacking layer B301.

In various embodiments, the wound dressing B300 can have an absorbentmaterial B302. The absorbent material B302 can be accompanied by theadditional components within the wound dressing as described withreference to the wound dressing cross-section in FIGS. 19A-B, such as atransmission layer and a masking or obscuring layer (not shown).

In some embodiments, the wound dressing B300 can have an absorbentmaterial B302 with a central portion B308. The absorbent material B302can have a longitudinal length and a transverse width. In someembodiments, the longitudinal length is greater than the transversewidth. In some embodiments, the longitudinal length and the transversewidth are of equal size. In various embodiments, the absorbent materialB302 can have a contoured shape with a substantially rectangular body.

The central portion B308 of the absorbent material B302 may comprise awaisted portion B303. The waisted portion B303 can be defined by thetransverse width of the absorbent material B302 narrowing at the centralportion B308 of the longitudinal length. For example, in someembodiments, the waisted portion B303 can be a narrow width at thecentral portion B308 of the absorbent material B302, as illustrated inFIGS. 20A-C. Additional embodiments of the waisted portion B303 arepossible including those described herein. Further, the shape of theaccompanying components within the wound dressing as described withreference to FIGS. 19A-C can be formed to the same contoured shape ofthe absorbent material including the waisted portion.

The waisted portion B303 can increase the flexibility of the wounddressing and can allow enhanced compatibility of the wound dressing tothe patient's body. For example, the narrow central region may allow forimproved contact and adhesion of the wound dressing to the skin surfacewhen the wound dressing is used on non-planar surfaces and/or wrappedaround an arm or leg. Further, the narrow central portion providesincreased compatibility with the patient's body and patient movement.

As in FIGS. 31A-B, embodiments of wound dressings may comprise variousconfigurations of slits (described in detail below) so as to furtherenhance conformability of the dressing in non-planar wounds. Also, asdescribed below, the absorbent layers may be colored or obscured with anobscuring layer, and optionally provided with one or more viewingwindows. The domed ports may also be replaced with one or more fluidicconnectors of the type described below in FIGS. 39A-B. Further, thewound dressing B300 can comprise all designs or embodiments hereindescribed or have any combination of features of any number of wounddressing embodiments disclosed herein.

FIG. 20B illustrates an embodiment of a wound dressing B300 with awaisted portion. A wound dressing B300 as illustrated in FIG. 20B canhave the features and embodiments as described above with reference toFIG. 20A. However, FIG. 20B illustrates an embodiment with a shorterlongitudinal length with respect to the transverse width. FIG. 20Cillustrates an additional embodiment of a wound dressing B300 with awaisted portion. As illustrated in FIG. 20C, the wound dressing can havea longitudinal length and a transverse width that are not substantiallydifferent in size, as opposed to a longitudinal length that issubstantially longer than the transverse width of the wound dressing asshown in the embodiments illustrated in FIGS. 20A and 20B. Theembodiments of a wound dressing illustrated in FIGS. 20B and 20C caninclude all features and embodiments described herein for wounddressings including those embodiments of the waisted portion B303described with reference to FIG. 20A.

FIGS. 21A-F, 22A-F, 23A-F, 24A-F, 25A-F, 26A-F, 27A-F, 28A-F, and 30illustrate additional embodiments of wound dressings. In theseembodiments, a waisted portion B408 is located inwardly with referenceto an edge B409 of the absorbent layer B402. Preferably, the contour ofthe absorbent layer B402 is curved from the edge B409 to the waistedportion B408, so as to form a smooth contour.

FIGS. 21A-F illustrate multiple views of an embodiment of a wounddressing with a waisted portion, obscuring layer, and viewing windows.FIG. 21A illustrates a perspective view of an embodiment of a wounddressing B400. The wound dressing B400 preferably comprises a port B406.The port B406 is preferably configured to be in fluid communication witha pump as described with reference to FIG. 17, and may include a tube orconduit pre-attached to the port. Alternatively, negative pressure canbe supplied to the wound dressing through other suitable fluidicconnectors, including but not limited to the fluidic connectors of thetype described below in FIGS. 39A-B.

The wound dressing B400 can be constructed similar to the embodiments ofFIGS. 19A and 19B above, and may comprise an absorbent material B402underneath or within a backing layer B405. Optionally, a wound contactlayer and a transmission layer may also be provided as part of the wounddressing B400 as described above. The absorbent material B402 cancontain a narrowed central or waisted portion B408, as describedpreviously to increase flexibility and conformability of the wounddressing to the skin surface. The backing layer B405 may have a borderregion B401 that extends beyond the periphery of the absorbent materialB402. The backing layer B405 may be a translucent or transparent backinglayer, such that the border region B401 created from the backing layerB405 can be translucent or transparent. The area of the border regionB401 of the backing layer B405 can be approximately equal around theperimeter of the entire dressing with the exception of the narrowedcentral portion, where the area of the border region is larger. One willrecognize that the size of the border region B401 will depend on thefull dimensions of the dressing and any other design choices.

As illustrated in FIG. 21A, provided at least at the top of or over theabsorbent layer B402 and under the backing layer B405 may be anobscuring layer B404 that optionally has one or more viewing windowsB403. The obscuring layer B404 may partially or completely obscurecontents (such as fluids) contained within the wound dressing B400and/or the absorbent material (i.e., within the absorbent material B402or under the backing layer B405). The obscuring layer may be a coloredportion of the absorbent material, or may be a separate layer thatcovers the absorbent material. In some embodiments, the absorbentmaterial B402 may be hidden (partially or completely), colored, ortinted, via the obscuring layer B404, so as to provide cosmetic and/oraesthetic enhancements, in a similar manner to what is described above.The obscuring layer is preferably provided between the topmost backinglayer B405 and the absorbent material B402, although otherconfigurations are possible. The cross-sectional view in FIGS. 19A and19B illustrates this arrangement with respect to the masking orobscuring layer B2107. Other layers and other wound dressing componentscan be incorporated into the dressing as herein described.

The obscuring layer B404 can be positioned at least partially over theabsorbent material B402. In some embodiments, the obscuring layer B404can be positioned adjacent to the backing layer, or can be positionedadjacent to any other dressing layer desired. In some embodiments, theobscuring layer B404 can be adhered to or integrally formed with thebacking layer and/or the absorbent material.

As illustrated in FIG. 21A, the obscuring layer B404 can havesubstantially the same perimeter shape and size as the absorbentmaterial B402. The obscuring layer B404 and absorbent material B402 canbe of equal size so that the entirety of the absorbent material B402 canbe obscured by the obscuring layer B404. The obscuring layer B404 mayallow for obscuring of wound exudate, blood, or other matter releasedfrom a wound. Further, the obscuring layer B404 can be completely orpartially opaque having cut-out viewing windows or perforations.

In some embodiments, the obscuring layer B404 can help to reduce theunsightly appearance of a dressing during use, by using materials thatimpart partial obscuring or masking of the dressing surface. Theobscuring layer B404 in one embodiment only partially obscures thedressing, to allow clinicians to access the information they require byobserving the spread of exudate across the dressing surface. The partialmasking nature of this embodiment of the obscuring layer enables askilled clinician to perceive a different color caused by exudate,blood, by-products etc. in the dressing allowing for a visual assessmentand monitoring of the extent of spread across the dressing. However,since the change in color of the dressing from its clean state to astate containing exudate is only a slight change, the patient isunlikely to notice any aesthetic difference. Reducing or eliminating avisual indicator of wound exudate from a patient's wound is likely tohave a positive effect on their health, reducing stress for example.

In some embodiments, the obscuring layer can be formed from a non-wovenfabric (for example, polypropylene), and may be thermally bonded using adiamond pattern with 19% bond area. In various embodiments, theobscuring layer can be hydrophobic or hydrophilic. Depending on theapplication, in some embodiments, a hydrophilic obscuring layer mayprovide added moisture vapor permeability. In some embodiments, however,hydrophobic obscuring layers may still provide sufficient moisture vaporpermeability (i.e., through appropriate material selection, thickness ofthe obscuring layer), while also permitting better retention of dye orcolor in the obscuring layer. As such, dye or color may be trappedbeneath the obscuring layer. In some embodiments, this may permit theobscuring layer to be colored in lighter colors or in white. In thepreferred embodiment, the obscuring layer is hydrophobic. In someembodiments, the obscuring layer material can be sterilizable usingethylene oxide. Other embodiments may be sterilized using gammairradiation, an electron beam, steam or other alternative sterilizationmethods. Additionally, in various embodiments the obscuring layer cancolored or pigmented, e.g., in medical blue. The obscuring layer mayalso be constructed from multiple layers, including a colored layerlaminated or fused to a stronger uncolored layer. Preferably, theobscuring layer is odorless and exhibits minimal shedding of fibers.

The absorbent layer B402, itself may be colored or tinted in someembodiments, however, so that an obscuring layer is not necessary. Thedressing may optionally include a means of partially obscuring the topsurface. This could also be achieved using a textile (knitted, woven, ornon-woven) layer without openings, provided it still enables fluidevaporation from the absorbent structure. It could also be achieved byprinting an obscuring pattern on the top film, or on the top surface ofthe uppermost pad component, using an appropriate ink or colored padcomponent (yarn, thread, coating) respectively. Another way of achievingthis would be to have a completely opaque top surface, which could betemporarily opened by the clinician for inspection of the dressing state(for example through a window), and closed again without compromisingthe environment of the wound.

Additionally, FIG. 21A illustrates an embodiment of the wound dressingincluding one or more viewing windows B403. The one or more viewingwindows B403 preferably extend through the obscuring layer B404. Theseviewing windows B403 may allow visualization by a clinician or patientof the wound exudate in the absorbent material below the obscuringlayer. FIG. 21A illustrates an array of dots (e.g., in one or moreparallel rows) that can serve as viewing windows B403 in the obscuringlayer B404 of the wound dressing. In a preferred embodiment, two or moreviewing windows B403 may be parallel with one or more sides of thedressing B400. In some embodiments, the one or more viewing windows maymeasure between 0.1 mm and 20 mm, preferably 0.4 mm to 10 mm, and evenmore preferably, 1 mm to 4 mm.

The viewing windows B403 may be cut through the obscuring layer B404 ormay be part of an uncolored area of the obscuring layer B404 andtherefore may allow visualization of the absorbent material B402. Theone or more viewing windows B403 can be arranged in a repeating patternacross the obscuring layer B404 or can be arranged at random across theobscuring layer. Additionally, the one or more viewing windows can be acircular shape or dots. Preferably, the one or more viewing windows B403are configured so as to permit not only the degree of saturation, butalso the progression or spread of fluid toward the fluid port B406, asin some embodiments, dressing performance may be adversely affected whenthe level of fluid has saturated the fluid proximate the port B406. Insome embodiments, a “starburst” array of viewing windows B403 emanatingaround the port B406 may be suitable to show this progression, althoughof course other configurations are possible.

In FIG. 21A, the viewing windows B403 correspond to the area of theabsorbent material B402 that is not covered by the obscuring layer B404.As such, the absorbent material B402 is directly adjacent the backinglayer B405 in this area. Since the obscuring layer B404 acts as apartial obscuring layer, the viewing windows B403 may be used by aclinician or other trained user to assess the spread of wound exudatethroughout the dressing. In some embodiments, the viewing windows B403can comprise an array of dots or crescent shaped cut-outs. For example,an array of dots as viewing windows B403 are illustrated in FIGS. 21A-F,22A-F, 23A-F, 24A-F, 25A-F, 26A-F, 27A-F, and 28A-F in which the arrayof dots are arranged in an 5×2, 3×2, 8×1, 5×1, 3×1, 3×3, 3×3, andquincunx array respectively. Additionally, in some embodiments, the dotpattern can be distributed evenly throughout the obscuring layer andacross the entire or substantially the entire surface of the obscuringlayer. In some embodiments, the viewing windows B403 may be distributedrandomly throughout the obscuring layer. Preferably, the area of theobscuring layer B404 uncovered by the one or more viewing windows B403is balanced to as to minimize the appearance of exudate while permittingthe inspection of the dressing B400 and/or absorbent material B402. Insome embodiments, the area exposed by the one or more viewing windowsB403 does not exceed 20% of the area of the obscuring layer B404,preferably 10%, and even more preferably 5%.

The viewing windows B403 may take several configurations, as will bediscussed in relation to FIGS. 32-34. In FIG. 33, the viewing windowsB403 may comprise an array of regularly spaced uncolored dots (holes)made into the obscuring layer B404. While the dots illustrated here arein a particular pattern, the dots may be arranged in differentconfigurations, or at random. The viewing windows B403 are preferablyconfigured so as to permit a patient or caregiver to ascertain thestatus of the absorbent layer, in particular to determine its saturationlevel, as well as the color of the exudate (e.g., whether excessiveblood is present). By having one or more viewing windows, the status ofthe absorbent layer can be determined in an unobtrusive manner that isnot aesthetically unpleasing to a patient. Because a large portion ofthe absorbent layer may be obscured, the total amount of exudate maytherefore be hidden. As such, the status and saturation level of theabsorbent layer B402 may therefore present a more discreet externalappearance so as to reduce patient embarrassment and visibility andthereby enhance patient comfort. In some configurations, the one or moreviewing windows B403 may be used to provide a numerical assessment ofthe degree of saturation of the dressing B400. This may be doneelectronically (e.g., via a digital photograph assessment), or manually.For example, the degree of saturation may be monitored by counting thenumber of viewing windows B403 which may be obscured or tinted byexudate or other wound fluids.

In some embodiments, the absorbent layer B402 or the obscuring layerB404, in particular the colored portion of the absorbent layer, maycomprise (or be colored because of) the presence of an auxiliarycompound. The auxiliary compound may in some embodiments be activatedcharcoal, which can act to absorb odors. The use of antimicrobial,antifungal, anti-inflammatory, and other such therapeutic compounds isalso possible. In some embodiments, the color may change as a functionof time (e.g., to indicate when the dressing needs to be changed), ifthe dressing is saturated, or if the dressing has absorbed a certainamount of a harmful substance (e.g., to indicate the presence ofinfectious agents). In some embodiments, the one or more viewing windowsB403 may be monitored electronically, and may be used in conjunctionwith a computer program or system to alert a patient or physician to thesaturation level of the dressing B400.

FIG. 32 illustrates an embodiment of a dressing containing a viewingwindow in the shape of a trademarked brand name (“PICO”). FIG. 34illustrates an embodiment of a dressing comprising a viewing window inthe shape of a logo, here, the Smith & Nephew logo. Of course, manyother configurations are possible, including other graphics, texts, ordesigns. The graphical or textual elements present in the viewing windowmay also be, for example, instructional in nature.

In other alternatives, instructions may be given to change the wounddressing when the exudate reaches a predetermined distance from the edgeof the wound dressing, such as 5 mm from the wound dressing edge or 7 mmfrom the wound dressing edge, etc. Alternatively a ‘traffic light’system may be implemented whereby an electronic indicator shows green,amber or red light to indicate the spread of exudate in the wounddressing. Alternatively or additionally, another suitable indicator maybe used for indicating the spread of exudate over the dressing.

FIGS. 21A-F illustrate multiple views of the wound dressing B400. FIG.21A illustrates a perspective view of a wound dressing with thedimensions of 300 mm×150 mm. FIGS. 21B and 21C illustrate a top view andbottom view of the embodiment of a wound dressing described in FIG. 21A.FIGS. 21D and 21E illustrate a front and back view respectively of thewound dressing B400 described in FIG. 21A. FIG. 21F illustrates a sideview of the wound dressing as described in FIG. 21A.

Embodiments of the wound dressings described herein may be arranged suchthat each embodiment may have enhanced compatibility with body movement.This can be achieved by using a different shape for different woundtypes or areas of the body. Wound dressing embodiments can be of anysuitable shape or form or size as illustrated in FIGS. 21A-F, 22A-F,23A-F, 24A-F, 25A-F, 26A-F, 27A-F, 28A-F, and 40A-F. The overalldimensions of the dressings as illustrated in FIGS. 21A-F, 22A-F, 23A-F,24A-F, 25A-F, 26A-F, 27A-F, 28A-F may be, for example but withoutlimitation, 300 mm×150 mm, 200 mm×150 mm, 400 mm×100 mm, 300 mm×100 mm,200 mm×100 mm, 250 mm×250 mm, 200 mm×200 mm, and 150 mm×150 mm,respectively, although any total size may be used, and the size may bedetermined to match particular wound sizes. The oval-shaped dressing inFIGS. 40A-F may, in some embodiments, measure 190 mm×230 mm, or 145.5mm×190 mm. Again, it will be understood that the embodiments describedin the foregoing are simply illustrative embodiments illustratingpossible sizes, dimensions, and configurations of wound dressings, andthat other configurations are possible.

As noted above, the preceding embodiments illustrated in FIGS. 21A-F,22A-F, 23A-F, 24A-F, 25A-F, 26A-F, 27A-F and 28A-F may comprise awaisted portion B408 located inwardly with reference to an edge B409 ofthe absorbent layer B402. The contour of the absorbent layer to thewaisted portion B408 is preferably rounded and smooth. In theembodiments of FIGS. 21A-F, 22A-F, 23A-F, 24A-F and 25A-F, the inwarddistance between the edge B409 and the waisted portion B408 may rangefrom 1 mm, 5 mm, 10 mm, 15 mm, 20 mm, and 30 mm. Preferably, the inwarddistance is 10 mm. In the embodiments of FIGS. 26A-F, 27A-F, and 28A-Fthe inward distance between the edge B409 and the waisted portion B408may range from 5 mm, 10 mm, 20 mm, 30 mm, 40 mm, 45 mm, 50 mm, 60 mm,and 75 mm. FIGS. 22A-F illustrate a perspective view, a top view, abottom view, a front view, a back view, and a side view, respectively,of an embodiment of a wound dressing B400. In some embodiments, thedressing may measure 200 mm×150 mm. The wound dressing B400 of FIGS.22A-F can have a similar configuration and components as described abovefor FIGS. 21A-F, except the embodiments of FIG. 22A-F are of a smallersize. Additionally, in contrast to the embodiment of FIGS. 21A-F whichcomprises a 5×2 configuration of an array of dots viewing windows, theembodiment of FIGS. 22A-F comprises a viewing window configurationcomprising a 3×2 array of dots.

FIGS. 23A-F illustrate a perspective view, a top view, a bottom view, afront view, a back view, and a side view, respectively, of an embodimentof a wound dressing B400. In some embodiments, the dressing may measure400 mm×100 mm. The wound dressing B400 of FIGS. 23A-F can have a similarconfiguration and components as described above for FIGS. 21A-F, exceptthe embodiments of FIG. 23A-F are of a different size. Additionally, incontrast to the embodiment of FIGS. 21A-F, the embodiment of FIGS. 23A-Fcomprises a viewing window configuration comprising an 8×1 array ofdots.

FIGS. 24A-F illustrate a perspective view, a top view, a bottom view, afront view, a back view, and a side view, respectively, of an embodimentof a wound dressing B400. In some embodiments, the dressing may measure300 mm×100 mm. The wound dressing B400 of FIGS. 24A-F can have a similarconfiguration and components as described above for FIGS. 21A-F, exceptthe embodiments of FIG. 24A-Fare of a different size. Additionally, incontrast to the embodiment of FIGS. 21A-F, the embodiment of FIGS. 24A-Fcomprises a viewing window configuration comprising a 5×1 array of dots.

FIGS. 25A-F illustrate a perspective view, a top view, a bottom view, afront view, a back view, and a side view, respectively, of an embodimentof a wound dressing B400. In some embodiments, the dressing may measure200 mm×100 mm. The wound dressing B400 of FIGS. 25A-F can have a similarconfiguration and components as described above for FIGS. 21A-F, exceptthe embodiments of FIG. 25A-F are of a different size. Additionally, incontrast to the embodiment of FIGS. 21A-F, the embodiment of FIGS. 25A-Fcomprises a viewing window configuration comprising a 3×1 array of dots.

FIGS. 28A-F illustrate a perspective view, a top view, a bottom view, afront view, a back view, and a side view, respectively, of an embodimentof a wound dressing B400. In some embodiments, the dressing may measure150 mm×150 mm. The wound dressing B400 of FIGS. 28A-F can have a similarconfiguration and components as described above for FIGS. 21A-F, exceptthe embodiments of FIGS. 25A-F are of a different size. Additionally, incontrast to the embodiment of FIGS. 21A-F, the embodiment of FIGS. 28A-Fcomprises a viewing window configuration comprising a quincunx array ofdots. The quincunx array of dots configuration consists of five dotsarranged in a cross, with four of the dots forming a square or rectanglewhere one dot is positioned at each of the four corners of the square orrectangle shaped wound dressing and a fifth dot in the center. However,one corner of the wound dressing preferably has the fluidic connector orport B406 in place of a dot in the quincunx dot array.

FIGS. 26A-F illustrate a perspective view, a top view, a bottom view, afront view, a back view, and a side view, respectively, of an embodimentof a wound dressing B400. In some embodiments, the dressing may measure250 mm×250 mm. The wound dressing B400 of FIGS. 26A-F can have a similarconfiguration and components as described above for FIGS. 21A-F, exceptthe embodiments of FIGS. 26A-Fare of a different size. Additionally, incontrast to the embodiment of FIGS. 21A-F, the embodiment of FIGS. 26A-Fcomprises a viewing window configuration comprising a 3×3 array of dotswith an absent dot at a corner position of the wound dressing and in itsplace is a domed port or a fluidic connector B406 completing the 3×3array.

FIGS. 27A-F illustrate a perspective view, a top view, a bottom view, afront view, a back view, and a side view, respectively, of an embodimentof a wound dressing B400. In some embodiments, the dressing may measure200 mm×200 mm. The wound dressing B400 of FIGS. 27A-F can have a similarconfiguration and components as described above for FIGS. 21A-F, exceptthe embodiments of FIGS. 27A-F are of a different size. Additionally, incontrast to the embodiment of FIGS. 21A-F, the embodiment of FIGS. 27A-Fcomprises a viewing window configuration comprising a 3×3 array of dotswith an absent dot at a corner position of the wound dressing and in itsplace is a domed port or a fluidic connector completing the 3×3 array.

The additional sizes and shapes illustrated in FIGS. 21A-F, 22A-F,23A-F, 24A-F, 25A-F, 26A-F, 27A-F, 28A-F, and 40 may incorporate thewaisted portion B408, obscuring layer B404, viewing windows B403, andother components and embodiments described herein.

FIGS. 29A, 29B, and 30 illustrate embodiments of a dressing B500comprising one or more orifice viewing windows B502 at, near, oradjacent to the port. The orifice viewing windows B502 can be providedat, near, adjacent to the port B504 in the backing layer for viewing ofthe absorbent material B503 present in proximity to the port B504. Theorifice viewing windows B502 can have the same structure and/or functionas the viewing windows herein described. In some embodiments, theorifice viewing window B502 can be formed from a cross-shaped orMaltese-cross-shaped aperture or cut-out B501 in the obscuring layer.The arms of the cross-shaped cut-out B501 can be aligned with thelongitudinal length and transverse width of the absorbent material B503as shown in FIG. 29A. Alternatively, the arms of the cross-shapedcut-out B501 can be offset from the longitudinal length and transversewidth of the absorbent material, at an angle, for example, a 45° angle,as illustrated in FIG. 29B. The arms of the cross-shaped cut-out mayspan a larger dimension than a hole in the absorbent material below thecut-out B501. For example, the arms may span a dimension of about 25 mm,while the through-hole in the absorbent material may have a diameter of10 mm.

Additionally, FIG. 30 illustrates an embodiment of a wound dressing B600in which the arms of the cross-shaped aperture can have flared edgesB601. The orifice viewing windows B502 at, near, or adjacent to the portB604 may be used to indicate that fluid is approaching the port B604 orthat the dressing B600 is otherwise becoming saturated. This can assistthe clinician or patient in maintaining the wound dressing anddetermining when to change the dressing, because once fluid contacts thecenter of the port, such fluid contact may at least partially occludethe hydrophobic filter that may be contained therein so as to interruptor at least partially block the application of negative pressure. Theorifice viewing windows B502 can be used with the fluidic connector aswell as the domed port or any other suitable connector.

As with FIGS. 31A and 31B, the wound dressing may also be provided withone or more slits B2150 to aid the dressing in conforming to anon-planar area. FIG. 31A illustrates an embodiment of a wound dressingB2100 with a narrowed central portion or waisted portion B2120 andconcentric slits B2150. This embodiment may be useful for the treatmentof wounds on non-planar surfaces or otherwise contoured wounds,including, for example, feet, knees, sacral regions, or other suchareas. In some embodiments, the wound dressing B2100 may provide for oneor more slits B2150 cut into the dressing, preferably into the absorbentlayer, that may enhance the conformability of the dressing. In thisembodiment, the slits B2150 are cut in concentric ovoid arcs, althoughother configurations (as discussed below) are possible. Preferably, thearea under the port B2130 or fluidic connector disposed at the top ofthe device is free from the slits B2150, as this may interfere withfluid transfer from the dressing. In some embodiments, the slits B2150may be formed as part of, in addition to, or instead of baffles that maybe present within the absorbent layer so as to may aid in distributionof wound exudate. In these embodiments, and with all other embodimentsdescribed herein, although a domed connector is shown attached to thedressing, this may be interchanged with any other suitable connector,including for example embodiments of the fluidic connectors described inFIGS. 39A and 39B (as described below).

FIG. 31B illustrates an embodiment of a wound dressing B2100 with anarrow central portion B2120. Here, however, one or more slits B2150extending across the width of the dressing may be present. Preferably,these slits B2150 do not extend entirely across the width of thedressing, in order to promote fluid transfer within the absorbent layer.The slits B2150 may enhance conformability of the dressing, possibly inconjunction with the waisted configuration of the dressing, when appliedto a non-planar or contoured wound area. For example, such a dressingB2100 may be useful when applied so as to wrap around an arm or a leg.

FIGS. 39A and 39B illustrate embodiments of white and black fluidicconnectors B2410, B2420, respectively, that may be used to connect anembodiment of a wound dressing described herein to a source of negativepressure. In some embodiments, the domed port used in other embodimentsdiscussed herein (e.g., as illustrated above in FIG. 17) may be replacedby the fluidic connector B2410, B2420, for example as illustrated inFIGS. 32-35. The fluidic connector B2410, B2420 may be flexible and/orenhance the comfort of the patient. The fluidic connector B2410, B2420preferably comprises a fluidic connector body configured to transmitfluid through itself, including, for example, negative pressure and/orwound exudate. The fluidic connector body is preferably encapsulatedwithin one or more layers of fluid-impermeable material. In someembodiments, the fluid-impermeable material is heat-sealed together toenclose the fluid connector body.

With reference now to FIG. 39A, the body of the fluidic connector B2410is preferably be constructed from a material configured to transmitfluids therethrough, including fabrics such as 3D fabric. In someembodiments, the thickness of the fluidic connector body may measurebetween 0.5 to 4 mm, preferably 0.7 to 3 mm, and even more preferablybetween 1 and 2 mm; in a preferred embodiment the fluid connector bodyis 1.5 mm thick. Suitable materials that may be used for the fluidicconnector body, including the 3D fabric, are disclosed in U.S.application Ser. No. 13/381,885, filed Dec. 30, 2011, published asUS2012/0116334, titled “APPARATUSES AND METHODS FOR NEGATIVE PRESSUREWOUND THERAPY,” and which is hereby incorporated by reference in itsentirety. Use of the 3D fabric in the fluidic connector body may helpalleviate fluid blockage when the connector is kinked, and may furtherprovide for a soft fluidic connector that alleviates contact pressureonto a patient, for example when the patient's weight is pressed againstthe fluidic connector. This may enhance patient comfort and reduce thelikelihood of pressure ulcers.

Testing of various weights in various configurations on embodiments offluidic connectors comprising a 3D fabric was completed. The testingincluded weights above those believed to be likely to be encountered bya patient, as maximal pressure on a heel for a patient using dressingswas found to be 1.3 kg/cm² in some studies. Preferably, embodiments ofthe fluidic connectors described herein, especially when comprising 3Dfabric, can transmit therapeutic levels of negative pressure (i.e., inan amount sufficient to heal a wound) while a weight is pressed downthereupon. For example, embodiments are preferably able to transmittherapeutic levels of negative pressure while an external pressureapplied on the dressing and/or 3D fabric of up to 1 kg/cm², preferablyup to 2 kg/cm², and even more preferably up to 4 kg/cm². Certainembodiments, as described below, have been tested as being capable oftransmitting therapeutic levels of negative pressure while an externalpressure applied on the dressing and/or 3D fabric is above 6 kg/cm².

In the testing, a 400 ml wound cavity was used, and pressure wasmeasured both at the wound and at the pump. Embodiments of a fluidicconnector comprising 3D fabric were tested when laid flat with a weightplaced thereupon. Testing indicated that when no pressure was applied tothe fluidic connector, the pressure differential between the pressure atthe pump and at the cavity was approximately 2 mmHg. Various differentweights were applied, ranging between 2 and 12 kg/cm², in 2 kgincrements, and the resulting pressure difference was approximatelylinear, with the pressure difference at 12 kg/cm² being calculated at 33mmHg, while the pressure difference at 2 kg/cm² being only 16 mmHg. Therelation between the pressure difference in mmHg was found to equalapproximately 4.5 times the applied load in kg/cm². Testing alsoindicated that the relative pressure difference between the pressure atthe pump and the pressure at the wound after five minutes was less than10 mmHg when measured at the pump for loads under 4 kg/cm², and under 20mmHg when measured at the wound for loads under 4 kg/cm².

Testing was also performed with a weight laid on an embodiment of afluidic connector, while being bent at a 90° angle. Various differentweights were applied, ranging between 2 and 12 kg/cm², in 2 kgincrements, and the resulting pressure difference was approximatelylinear, with the pressure difference at 12 kg/cm² being calculated at 51mmHg, while the pressure difference at 2 kg/cm² being 17 mmHg. Therelation between the pressure difference in mmHg was found to equalapproximately 8 times the applied load in kg/cm². Testing also indicatedthat the relative pressure difference between the pressure at the pumpand the pressure at the wound after five minutes was approximately 20mmHg when measured at the pump for loads under 4 kg/cm², and under 30mmHg when measured at the wound for loads under 4 kg/cm².

Further testing was performed with a weight laid on an embodiment of afluidic connector, while being bent at a 180° angle (i.e., folded overitself). Various different weights were applied, ranging between 2 and12 kg/cm², in 2 kg increments, and the resulting pressure difference wasapproximately linear, with the pressure difference at 12 kg/cm² beingcalculated at 76 mmHg, while the pressure difference at 2 kg/cm² being25 mmHg. The relation between the pressure difference in mmHg was foundto equal approximately 10.7 times the applied load in kg/cm². Testingalso indicated that the relative pressure difference between thepressure at the pump and the pressure at the wound after five minuteswas approximately 20 mmHg when measured at the pump for loads under 4kg/cm², and under 30 mmHg when measured at the wound for loads under 4kg/cm².

Testing was also performed on different widths and thicknesses of 3Dfabric that may be used in embodiments of fluidic connectors describedherein. In a particular example, the maximum negative pressure thatcould be applied using 3D fabric measuring 1, 1.25, 1.5, 1.75, and 2 cmin width was found to be between 85 and 92 mmHg, respectively. Uponapplication of an applied load of 1 kg/cm², however, the maximumnegative pressure applied for a 1 cm-width embodiment dropped to 75mmHg, while the 1.25 and 1.5 cm-width embodiments were essentiallyunchanged, exhibiting pressures between 85 and 90 mmHg. Application of a1 kg/cm² weight made the 1 cm-width embodiment maximum negative pressuredrop to about 73 mmHg, while the 1.25 cm-width embodiment dropped toabout 84 mmHg. The 1.5 cm-width embodiment showed a minimal maximumnegative pressure change down to approximately 86 mmHg. As tested, thegreatest increases in flow rate (as evidenced by the maximal negativepressures applied) were greatest when increasing the width of the 3Dfabric from 1 cm to 1.25 cm, and stabilized above 1.5 cm. Similarly,increasing the width of the 3D fabric (i.e., above 1 cm) was found toslightly reduce the amount of time required to pump a wound cavity downto a target negative pressure.

Further testing with single and double layers of Baltex 3540 3D fabric,either single or double thickness, indicated that while the maximumnegative pressure applied using a single thickness fabric dropped fromabout 88 mmHg with no applied weight to about 73 mmHg with a 2 kg/cm²weight. However, a double thickness fabric showed minimal change in themaximum amount of negative pressure applied, dropping from 90 mmHg withno weight applied to about 87 mmHg with an applied load of 2 kg/cm².

Depending on the particular application, using wider and/or thicker 3Dfabric may permit improved air flow, together with greater pressure andkink resistance in some context; this may be useful especially if higherabsolute negative pressure need to be applied to the wound. However, thegreater kink and pressure resistance may need to be balanced with otherconcerns such as perceived bulk and size of the fluidic connector,aesthetics, and comfort, which may require use of a thinner 3D fabric.

In some embodiments, the proximal end B2411 of the fluidic connectorB2410 is configured to be connected to a tube or other conduit that isin fluid communication with a source of negative pressure via the fluidconnector body, although some embodiments may provide for the fluidicconnector B2410 to be directly connectable to a source of negativepressure without needing a conventional tube. The distal end B2412 ofthe fluidic connector B2410 may be enlarged, and is configured to beattached and/or adhered to a dressing, for example via an aperture inthe backing layer of the dressing and/or in the fluidic connector B2410,so that the fluid connector body is in fluid communication therewith.

In one configuration and as illustrated in FIG. 39A, the distal endB2412 of the fluidic connector B2410 may be convex on one side and flaton the opposite side. As illustrated in FIGS. 32-34 below, the flat sidemay be aligned with the edge of the absorbent layer with the convex sideextending over the aperture in the backing layer. The fluidic connectorB2410 may be provided preattached to the dressing portion, or may beprovided in an unattached format so as to be connectable to the dressingportion by the patient or caregiver. The enlarged distal end B2412 mayaid in providing a larger area capable of transmitting negative pressureto the dressing, although the distal end may be provided without anyenlargement. Although preferred embodiments of the fluidic connectorB2410 are used in dressings that contain substantially all wound exudatewithin the absorbent material, such that the fluidic connector transmitsessentially only air, some embodiments of the fluidic connector may beconfigured so as to transfer exudate in addition to air. In embodimentsof the fluidic connector that are configured to transfer essentiallyonly air (while wound exudate remains substantially within the absorbentmaterial), the distal end of the fluidic connector is preferablyprovided with a filter configured to block fluid transport beyonditself, such as a hydrophobic filter. An example of such a configurationis described in U.S. Provisional Application Ser. No. 61/650,904, filedMay 23, 2012, titled “APPARATUSES AND METHODS FOR NEGATIVE PRESSUREWOUND THERAPY,” and which is hereby incorporated into this presentapplication in its entirety.

In embodiments of the fluidic connector that are configured to transferexudate in addition to air, the fluidic connector may be provided with asecondary air leak channel configured to provide a flow of ambient airto the wound site. Preferably, the secondary air leak channel isprovided with a filter to prevent contamination of the wound.

Turning now to FIG. 39B, this figure shows an embodiment similar to FIG.39A, but where the fluidic connector B2420 may appear colored, forexample as a result of an obscuring layer similar to that previouslydescribed. In some embodiments, obscuring coloration may be provided bydyeing the material used in the fluidic connector B2420, for example the3D fabric that may be used therein. In some embodiments, the obscuringlayer may be placed above the 3D fabric, either above or below thefluid-impermeable material. In some embodiments, the encapsulatingfluid-impermeable material may be colored or tinted. Coloring thefluidic connector B2420 (e.g, via the obscuring layer) may enhance theaesthetic appeal of the device, help in disguising or making the deviceless obtrusive (in particular when the fluidic connector is visible toothers), and, when the fluidic connector is used to transfer exudatesaway from the wound, may hide the presence of the exudates therein.

In some embodiments, the fluidic connector body may be colored as aresult of an auxiliary compound such as activated charcoal. Further,some embodiments may provide for text or images to be printed thereon,for example for instructional or advertising purposes. Such improvementsmay enhance patient comfort and minimize embarrassment, therebyincreasing patient compliance and satisfaction with the device. Theobscuring layer in the fluidic connector can have all features describedwith reference to the obscuring layer of the wound dressing as hereindescribed.

FIG. 33 illustrates an embodiment of a wound dressing B720 thatcomprises a hexagonal backing layer and a three-lobed configuration forthe absorbent material and the obscuring layer. This wound dressingB720, as with several other embodiments described herein, may beadvantageously applied to wounds or areas surrounding wounds that arelocated in non-planar areas. The embodiment illustrated here may beparticularly advantageous when applied to protruding body portions, forexample elbows and heels.

FIG. 34 illustrates a wound dressing B730 with a three-lobedconfiguration similar in some respects to the embodiment illustrated inFIG. 33. Here, however, the dressing is smaller and comprises morerounded projections. FIGS. 32-34 illustrate a fluidic connector B721,B731 similar to those described in FIGS. 39A and 39B attached to thedevice, with the flat end aligned with the edge of the absorbentmaterial and the convex end extending over an aperture in the backinglayer. This fluidic connector may enhance comfort and prevent pressureulcers or other complications that may result from extended pressure ofa conventional tube onto the wound or skin surrounding the wound (asdescribed above). Of course, different connectors may be used, such asthe domed port illustrated in FIG. 17.

FIGS. 35-36 also illustrate additional embodiments of wound dressingsB740, B750 with three-lobed configurations for the absorbent materialand a hexagonal backing layer. The wound dressing B750 illustrated inFIG. 36 is larger where the lobes of the absorbent material comprisesflared ends, while the wound dressing B740 illustrated in FIG. 35 issmaller and the absorbent material does not have flared ends. Allsuitable fluidic connectors or conduits may be used, and the domed portconnector of FIG. 36 may be used in place of the fluidic connector ofFIG. 35, and vice versa. As with the preceding embodiments, theabsorbent layers may be colored or obscured, and one or more slits maybe formed onto the absorbent layers to enhance conformability tonon-planar surfaces. It will be appreciated that in the embodiments ofFIGS. 33-36, the number of lobes may be varied, and the backing layercan have other shapes, and is not limited to being hexagonal.

Additionally, FIGS. 37A-C and 38 illustrate embodiments of a wounddressing B760, B770, B780, B790 that comprises a four-lobedconfiguration. Although these embodiments are illustrated without a portor fluidic connector attached thereto, it will of course be understoodthat such ports and fluidic connectors are envisioned and may beattached in a similar fashion as described previously herein. FIGS.37A-C comprise embodiments of a four-lobed wound dressing comprising anobscuring layer and viewing windows extending through the obscuringlayer. The viewing windows can be used as discussed above forvisualization of wound exudate in the absorbent layer. Examples of suchviewing windows are illustrated in FIGS. 37A and 37B. The dressing B760shown in FIG. 37A includes an obscuring layer B762 and crescent-shapedviewing windows B764 provided in the obscuring layer to extend throughthe obscuring layer allowing visibility of the dressing therebelow. Thedressing B770 of FIG. 37B includes an obscuring layer B772 and a numberof holes B774 therethrough acting as viewing windows for viewing thestate of the dressing therebelow. FIG. 37C shows another dressing B780including an obscuring layer B782 with viewing windows B784. With thedressings B760, B770, B780 the progress of exudate spread over thedressing and towards the edge of the dressing can be monitored.

FIG. 38 illustrates a perspective view of an embodiment of a wounddressing B790 according to an embodiment of the four-lobe configuration.FIG. 38 shows a possible four-lobe configuration of a dressing, usefulfor enhanced compatibility with body movement, where each layer isshaped to reduce the incident angle of the pad edge, and to providesomewhat independently moving sub-sections of the dressing. The dressingborder, including the wound contact layer B791 and the backing layerB792 can also comprise slits, provided to further enhance theconformability on application by allowing the borders to overlap ifneeded. The wound dressing with a four-lobe configuration, as well asother configurations, are described in detail in InternationalApplication PCT/GB2012/000587, titled “WOUND DRESSING AND METHOD OFTREATMENT” and filed on Jul. 12, 2012, published as WO 2013/007973 A2 onJan. 17, 2013, which is incorporated by reference herein.

Additionally, FIGS. 40A-F illustrate an embodiment of a wound dressingB2300 with an oval shaped absorbent layer B2308 having multiple lobesB2301. FIGS. 40A-F illustrate, respectively, perspective, top, bottom,left, right, and side views of an embodiment of the dressing B2300. Insome embodiments, the absorbent layer B2308 can have six lobes.Preferably, two or more lobes B2301 (e.g., six lobes) are provided onthe wound dressing B2300; the lobes B2301, and specifically, the gapsbetween the lobes B2301, aid the wound dressing B2300 in conforming tononplanar wounds. For example, it may be advantageous to use thedressing B2300 to conform around joints such as elbows and knees.

The dressing B2300 can have a rectangular or square shaped backing layerB2302, and in some embodiments, the overall dressing B2300 may measure190 mm×230 mm, or 145.5 mm×190 mm. Preferably, a fluidic connector suchas a port B2306 is attached to the dressing B2300, although it will ofbe recognized that the fluidic connector of FIGS. 39A-B may be usedinstead or in addition. Additionally, in some embodiments, the dressingB2300 can have an obscuring layer B2304 and one or more viewing windowsB2303 similar to that described for other embodiments herein. FIG. 40Aillustrates a perspective view of the dressing B2300, while FIG. 40Billustrates a top view, 40C a bottom view, and 40D-F represent views ofthe four sides of the dressing B2300.

FIG. 41 illustrates an embodiment similar in shape and overallconfiguration to the embodiments illustrated above in FIGS. 23A-F. Here,however, the dressing B500 comprises an orifice viewing window B502similar to that described in relation to FIGS. 29A-B and 30. The orificeviewing window B502 is preferably formed from a cross-shaped orMaltese-cross shaped aperture or cutout B501 in the obscuring layerB506. The backing layer B510 provided over the obscuring layerpreferably has an orifice B504 located at the center of the orificeviewing window B502. Reference number B504 can also be considered todesignate a port that may be provided in or over the backing layer B510to provide a connection to a source of negative pressure, for example, aport provided over the orifice in the backing layer as described above.A smaller orifice B505 may be located in the absorbent layer B503 thatis provided below the obscuring layer B506. The dressing B500 maycomprise one or more viewing windows B507; here, eight viewing windowsB507 are provided in a linear arrangement. The bottom side of thedressing B500 optionally comprises a layer of adhesive, over which arelease layer B513 may be placed. Lines B512 illustrate possiblelocations where breaks in the release liner B513 may be provided.

In a preferred embodiment, the dressing B500 illustrated here has alongitudinal length of approximately 400 mm, and a transverse width ofapproximately 100 mm. The central axis of each arm of the cutout B501 ofthe orifice viewing window B502 is preferably offset from thelongitudinal length and transverse width of the absorbent material, atan angle, for example, a 45° angle, as illustrated. The spacing betweeneach arm of the cutout B501 may be, as illustrated here, 72°, althoughit will of course be recognized that other angles and configurations arepossible. Lines B512, indicating possible locations where breaks in therelease liner B513 may be provided, can be located, for example, at 80mm, 40±4 mm, and 25±4 mm from each of the top and bottom edges of thedressing B500. As illustrated, the orifice or port B504 (and cutoutB501) are preferably centered on the transverse midline of the dressingB500, and situated approximately 52-55 mm from the top edge of thedressing B500. Although the location may be changed, it may bepreferable to locate the port B504 near or along a side, edge, or cornerof the dressing B500, which is then preferably elevated with respect tothe remainder of the dressing. This configuration may extend the life ofthe dressing, as fluid would be slower in saturating the absorbent layerbelow or near the orifice or port B504.

FIG. 42 illustrates an embodiment similar in shape and overallconfiguration to the embodiments illustrated above in FIGS. 24A-F. Here,however, the dressing B500 comprises an orifice viewing window B502 andcutout B501, with for example five linearly arranged viewing windowsB507, among other parts, that are similar to that described above inrelation to FIG. 41. In a preferred embodiment, the dressing B500illustrated here has a longitudinal length of approximately 300 mm, anda transverse width of approximately 100 mm. The spacing between each armof the cutout B501 may be, as illustrated here, 72°, although it will ofcourse be recognized that other angles and configurations are possible.Lines B512, indicating possible locations where breaks in the releaseliner B513 may be provided, can be located, for example, at 80 mm, 40±4mm, and 25±4 mm from each of the top and bottom edges of the dressingB500. As illustrated, the orifice or port B504 (and cutout B501) arepreferably centered on the transverse midline of the dressing B500, andsituated approximately 52-55 mm from the top edge of the dressing B500.

FIG. 43 illustrates an embodiment similar in shape and overallconfiguration to the embodiments illustrated above in FIGS. 25A-F. Here,however, the dressing B500 comprises an orifice viewing window B502 andcutout B501, with for example three linearly arranged viewing windowsB507, among other parts, that are similar to that described above inrelation to FIG. 41. In a preferred embodiment, the dressing B500illustrated here has a longitudinal length of approximately 200 mm, anda transverse width of approximately 100 mm. The spacing between each armof the cutout B501 may be, as illustrated here, 72°, although it will ofcourse be recognized that other angles and configurations are possible.Lines B512, indicating possible locations where breaks in the releaseliner B513 may be provided, can be located, for example, at 80 mm, 40±4mm, and 25±4 mm from each of the top and bottom edges of the dressingB500. As illustrated, the orifice or port B504 (and cutout B501) arepreferably centered on the transverse midline of the dressing B500, andsituated approximately 52-55 mm from the top edge of the dressing B500.

FIG. 44 illustrates an embodiment similar in shape and overallconfiguration to the embodiments illustrated above in FIGS. 21A-F. Here,however, the dressing B500 comprises an orifice viewing window B502 andcutout B501, with for example two rows of five linearly arranged viewingwindows B507, among other parts, that are similar to that describedabove in relation to FIG. 41. In a preferred embodiment, the dressingB500 illustrated here has a longitudinal length of approximately 300 mm,and a transverse width of approximately 150 mm. The spacing between eacharm of the cutout B501 may be, as illustrated here, 72°, although itwill of course be recognized that other angles and configurations arepossible. Lines B512, indicating possible locations where breaks in therelease liner B513 may be provided, can be located, for example, at 80mm, 40±4 mm, and 25±4 mm from each of the top and bottom edges of thedressing B500. As illustrated, the orifice or port B504 (and cutoutB501) are preferably centered on the transverse midline of the dressingB500, and situated approximately 52-55 mm from the top edge of thedressing B500.

FIG. 45 illustrates an embodiment similar in shape and overallconfiguration to the embodiments illustrated above in FIGS. 22A-F. Here,however, the dressing B500 comprises an orifice viewing window B502 andcutout B501, with for example two rows of three linearly arrangedviewing windows B507, among other parts, that are similar to thatdescribed above in relation to FIG. 41. In a preferred embodiment, thedressing B500 illustrated here has a longitudinal length ofapproximately 300 mm, and a transverse width of approximately 100 mm.The spacing between each arm of the cutout B501 may be, as illustratedhere, 72°, although it will of course be recognized that other anglesand configurations are possible. Lines B512, indicating possiblelocations where breaks in the release liner B513 may be provided, can belocated, for example, at 80 mm, 40±4 mm, and 25±4 mm from each of thetop and bottom edges of the dressing B500. As illustrated, the orificeor port B504 (and cutout B501) are preferably centered on the transversemidline of the dressing B500, and situated approximately 52-55 mm fromthe top edge of the dressing B500.

FIG. 46 illustrates an embodiment similar in shape and overallconfiguration to the embodiments illustrated above in FIGS. 26A-F. Here,however, the dressing B500 comprises an orifice viewing window B502 andcutout B501, with a 3×3 array of viewing windows absent a viewing windowat a corner position of the wound dressing, among other parts, that aresimilar to that described above in relation to FIG. 41 but located in acorner of the dressing B500. In a preferred embodiment, the dressingB500 illustrated here is approximately square, with each side measuringapproximately 250 mm. The spacing between each arm of the cutout B501may be, as illustrated here, 72°, although it will of course berecognized that other angles and configurations are possible. LinesB512, indicating possible locations where breaks in the release linerB513 may be provided, can be located, for example, at 80 mm, 40±4 mm,and 25±4 mm from each of the top and bottom edges of the dressing B500.As illustrated, the orifice or port B504 (and cutout B501) arepreferably centered on a corner of the dressing B500, and situatedapproximately 52-55 mm from the top edge of the dressing B500.

FIG. 47 illustrates an embodiment similar in shape and overallconfiguration to the embodiments illustrated above in FIGS. 27A-F. Here,however, the dressing B500 comprises an orifice viewing window B502 andcutout B501, with a 3×3 array of viewing windows absent a viewing windowat a corner position of the wound dressing, among other parts, that aresimilar to that described above in relation to FIG. 41 but located in acorner of the dressing B500. In a preferred embodiment, the dressingB500 illustrated here is approximately square, with each side measuringapproximately 200 mm. The spacing between each arm of the cutout B501may be, as illustrated here, 72°, although it will of course berecognized that other angles and configurations are possible. LinesB512, indicating possible locations where breaks in the release linerB513 may be provided, can be located, for example, at 80 mm, 40±4 mm,and 25±4 mm from each of the top and bottom edges of the dressing B500.As illustrated, the orifice or port B504 (and cutout B501) arepreferably centered on a corner of the dressing B500, and situatedapproximately 52-55 mm from the top edge of the dressing B500.

FIG. 48 illustrates an embodiment similar in shape and overallconfiguration to the embodiments illustrated above in FIGS. 28A-F. Here,however, the dressing B500 comprises an orifice viewing window B502 andcutout B501, with a quincunx array of viewing windows absent a viewingwindow at a corner position of the wound dressing, among other parts,that are similar to that described above in relation to FIG. 41 butlocated in a corner of the dressing B500. In a preferred embodiment, thedressing B500 illustrated here is approximately square, with each sidemeasuring approximately 150 mm. The spacing between each arm of thecutout B501 may be, as illustrated here, 72°, although it will of coursebe recognized that other angles and configurations are possible. LinesB512, indicating possible locations where breaks in the release linerB513 may be provided, can be located, for example, at 80 mm, B40±4 mm,and 25±4 mm from each of the top and bottom edges of the dressing B500.As illustrated, the port B504 (and cutout B501) are preferably centeredon a corner of the dressing B500, and situated approximately 52-55 mmfrom the top edge of the dressing B500.

FIG. 49A-B illustrates an embodiment somewhat similar in shape andoverall configuration to the embodiments illustrated above in FIGS.40A-F. Here, however, the oval-shaped dressing B500 comprises an orificeviewing window B502 and cutout B501, among other parts, that are similarto that described above in relation to FIG. 41. Viewing windows are notshown, but may be provided as in one embodiment as described above. In apreferred embodiment, the dressing B500 illustrated in FIG. 49A has alongitudinal length of approximately 250 mm, and a transverse width ofapproximately 200 mm. The longitudinal length of the absorbent layerB503 (and corresponding obscuring layer, if so provided) measuresapproximately 200 mm, with a transverse width of approximately 150 mm.The embodiment of the dressing B500 illustrated in FIG. 49B has alongitudinal length of approximately 200 mm, and a transverse width ofapproximately 150 mm. The longitudinal length of the absorbent layerB503 (and corresponding obscuring layer, if so provided) measuresapproximately 150 mm, with a transverse width of approximately 100 mm.Although no viewing windows B507 are illustrated, it will of course beunderstood that one or more such windows B507 may be provided on thedressing B500. The spacing between each arm of the cutout B501 may be72°, although it will of course be recognized that other angles andconfigurations are possible. As illustrated, the orifice or port B504(and cutout B501) are preferably centered on the transverse midline ofthe dressing B500, and situated approximately 52-55 mm from the top edgeof the dressing B500.

FIG. 50A illustrates an exploded view of a dressing B3400 for use innegative pressure wound therapy. Although this figure illustrates adressing having one particular shape, the construction of the layers canbe applied to any of the embodiments identified above, including FIGS.20A-30, 32-38, and 40A-49B. The dressing B3400 comprises a release layerB3480, wound contact layer B3460, a transmission layer B3450, anacquisition distribution layer B3440, an absorbent layer B3430, anobscuring layer B3420, and a backing layer B3410. The dressing B3400 maybe connected to a port, such as described below with respect to FIGS. 51and 52. At least the wound contact layer B3460, transmission layerB3450, absorbent layer B3430, obscuring layer B3420, and backing layerB3410 may have properties as described with respect to particularembodiments above, such as the embodiments of FIGS. 19A-38, and 40A-49B,as well as or instead of the properties described below.

The dressing B3400 may comprise a wound contact layer B3460 for sealingthe dressing B3400 to the healthy skin of a patient surrounding a woundarea. Certain embodiments of the wound contact layer may comprise threelayers: a polyurethane film layer, a lower adhesive layer and an upperadhesive layer. The upper adhesive layer may assist in maintaining theintegrity of the dressing B3400, and the lower adhesive layer may beemployed for sealing the dressing B3400 to the healthy skin of a patientaround a wound site. As described above, in some embodiments withrespect to FIGS. 19A-C, some embodiments of the polyurethane film layermay be perforated. Some embodiments of the polyurethane film layer andupper and lower adhesive layers may be perforated together after theadhesive layers have been applied to the polyurethane film. In someembodiments a pressure sensitive adhesive, which may be a silicone, hotmelt, hydrocolloid or acrylic based adhesive or other such adhesives,may be formed on both sides or optionally on a selected one side of thewound contact layer. In certain embodiments, the upper adhesive layermay comprise an acrylic pressure sensitive adhesive, and the loweradhesive layer may comprise a silicone pressure sensitive adhesive. Inother embodiments the wound contact layer B3460 may not be provided withadhesive. In some embodiments, the wound contact layer B3460 may betransparent or translucent. The film layer of the wound contact layerB3460 may define a perimeter with a rectangular or a square shape. Arelease layer B3480 may be removably attached to the underside of thewound contact layer B3460, for example covering the lower adhesivelayer, and may be peeled off using flaps B3481. Some embodiments of therelease layer B3480 may have a plurality of flaps extending along thelength of the layer B3480.

Some embodiments of the dressing B3400 may comprise an optional spaceror transmission layer B3450. The transmission layer B3450 may comprise aporous material or 3D fabric configured to allow for the passage offluids therethrough away from the wound site and into the upper layersof the dressing B3400. In particular, the transmission layer B3450 canensure that an open air channel can be maintained to communicatenegative pressure over the wound area even when the absorbent layerB3430 has absorbed substantial amounts of exudates. The transmissionlayer B3450 should remain open under the typical pressures that will beapplied during negative pressure wound therapy as described above, sothat the whole wound site sees an equalized negative pressure.

Some embodiments of the transmission layer B3450 may be formed of amaterial having a three dimensional structure. For example, a knitted orwoven spacer fabric (for example Baltex 7970 weft knitted polyester) ora non-woven fabric can be used. In some embodiments, the transmissionlayer B3450 can have a 3D polyester spacer fabric layer. This layer canhave a top layer which is a 84/144 textured polyester, and a bottomlayer which can be a 100 denier flat polyester and a third layer formedsandwiched between these two layers which is a region defined by aknitted polyester viscose, cellulose or the like monofilament fiber. Inuse, this differential between filament counts in the spaced apartlayers tends to draw liquid away from the wound bed and into a centralregion of the dressing B3400 where the absorbent layer B3430 helps lockthe liquid away or itself wicks the liquid onwards towards the coverlayer B3410 where it can be transpired. Other materials can be utilized,and examples of such materials are described in U.S. Patent Pub. No.2011/0282309, which are hereby incorporated by reference and made partof this disclosure. However, the transmission layer B3450 may beoptional, and for example may be optional in embodiments of the dressingB3400 which comprise the acquisition distribution layer B3440, describedbelow.

Some embodiments may comprise a wicking or acquisition distributionlayer (ADL) B3440 to horizontally wick fluid such as wound exudate as itis absorbed upward through the layers of the dressing B3400. Lateralwicking of fluid may allow maximum distribution of the fluid through theabsorbent layer B3430 and may enable the absorbent layer B3430 to reachits full holding capacity. This may advantageously increase moisturevapor permeation and efficient delivery of negative pressure to thewound site. Some embodiments of the ADL B3440 may comprise viscose,polyester, polypropylene, cellulose, or a combination of some or all ofthese, and the material may be needle-punched. Some embodiments of theADL B3440 may comprise polyethylene in the range of 40-150 grams persquare meter (gsm).

The dressing B3400 may further comprise an absorbent or superabsorbentlayer B3430. The absorbent layer can be manufactured from ALLEVYN™ foam,Freudenberg 114-224-4 and/or Chem-Posite™11C-450, or any other suitablematerial. In some embodiments, the absorbent layer B3430 can be a layerof non-woven cellulose fibers having super-absorbent material in theform of dry particles dispersed throughout. Use of the cellulose fibersintroduces fast wicking elements which help quickly and evenlydistribute liquid taken up by the dressing. The juxtaposition ofmultiple strand-like fibers leads to strong capillary action in thefibrous pad which helps distribute liquid.

For example, some embodiments of the absorbent layer B3430 may comprisea layered construction of an upper layer of non-woven cellulose fibers,superabsorbent particles (SAP), and a lower layer of cellulose fiberswith 40-80% SAP. In some embodiments, the absorbent layer B3430 may bean air-laid material. Heat fusible fibers can optionally be used toassist in holding the structure of the pad together. Some embodimentsmay combine cellulose fibers and air-laid materials, and may furthercomprise up to 60% SAP. Some embodiments may comprise 60% SAP and 40%cellulose. Other embodiments of the absorbent layer may comprise between60% and 90% (or between about 60% and about 90%) cellulose matrix andbetween 10% and 40% (or between about 10% and about 40%) superabsorbentparticles. For example, the absorbent layer may have about 20%superabsorbent material and about 80% cellulose fibers. It will beappreciated that rather than using super-absorbing particles or inaddition to such use, super-absorbing fibers can be utilized accordingto some embodiments of the present invention. An example of a suitablematerial is the Product Chem-Posite™ 11 C available from EmergingTechnologies Inc (ETi) in the USA.

Super-absorber particles/fibers can be, for example, sodium polyacrylateor carbomethoxycellulose materials or the like or any material capableof absorbing many times its own weight in liquid. In some embodiments,the material can absorb more than five times its own weight of 0.9% W/Wsaline, etc. In some embodiments, the material can absorb more than 15times its own weight of 0.9% W/W saline, etc. In some embodiments, thematerial is capable of absorbing more than 20 times its own weight of0.9% W/W saline, etc. Preferably, the material is capable of absorbingmore than 30 times its own weight of 0.9% W/W saline, etc. The absorbentlayer B3430 can have one or more through holes B3431 located so as tounderlie the suction port.

Some embodiments of the present disclosure may employ a masking orobscuring layer B3420 to help reduce the unsightly appearance of adressing B3400 during use due to the absorption of wound exudate. Theobscuring layer B3420 may be a colored portion of the absorbentmaterial, or may be a separate layer that covers the absorbent material.The obscuring layer B3420 may be one of a variety of colors such asblue, orange, yellow, green, or any color suitable for masking thepresence of wound exudate in the dressing B3400. For example, a blueobscuring layer B3420 may be a shade of blue similar to the shade ofblue commonly used for the material of medical gowns, scrubs, anddrapes. Some embodiments of the obscuring layer B3420 may comprisepolypropylene spunbond material. Further, some embodiments of theobscuring layer B3420 may comprise a hydrophobic additive or coating.Other embodiments may comprise a thin fibrous sheet of B60, 70, or 80gsm.

The obscuring layer may comprise at least one viewing window B3422configured to allow a visual determination of the saturation level ofthe absorbent layer. The at least one viewing window B3422 may compriseat least one aperture made through the obscuring layer. The at least oneviewing window B3422 may comprise at least one uncolored region of theobscuring layer. Some embodiments of the obscuring layer may comprise aplurality of viewing windows or an array of viewing windows, asdiscussed above with respect to FIGS. 41-48.

The masking capabilities of the obscuring layer B3420 should preferablyonly be partial, to allow clinicians to access the information theyrequire by observing the spread of exudate across the dressing surface.An obscuring layer B3420 may be partial due to material propertiesallowing wound exudate to slightly alter the appearance of the dressingor due to the presence of at least one viewing window B3422 in acompletely obscuring material. The partial masking nature of theobscuring layer B3420 enables a skilled clinician to perceive adifferent colour caused by exudate, blood, by-products etc. in thedressing allowing for a visual assessment and monitoring of the extentof spread across the dressing. However, since the change in colour ofthe dressing from its clean state to a state with exudate contained isonly a slight change, the patient is unlikely to notice any aestheticdifference. Reducing or eliminating a visual indicator of wound exudatefrom a patient is likely to have a positive effect on their health,reducing stress for example.

Tests performed upon various dressings with respect to the transmittanceproperties of the dressing indicate the ability of various samples tomask colour. The ability to mask colour may be calculated, for example,by measuring the reduction in absorption of light radiation atparticular wavelengths. The tests utilized a UV-Vis spectrophotometerJasco with integrating sphere, with a scanning range 340 to 800 nm,bandwidth 5 nm and B1000 nm/sec scanning speed. The data labelled blackbackground represents the extreme of exudate colour (the most colour anexudate might have)—the highest level of radiation absorbed and theleast amount of radiation reflected from the sample. The data for whitebackground represents the upper limit for total masking—generally thelowest level of radiation absorbed and the highest level of reflection.Sample 1 was a tinted polymer film placed over a black background, whichwas judged not to sufficiently mask the black background (representingwound exudate) satisfactorily. Sample 2 was a sheet of 3-dimensionalspacer fabric (Baltex 3D) placed over a black background, and was judgedto provide adequate masking of the black background. Sample 3 was asheet of non-woven material dyed green placed over a black background,and provided complete masking of the black background.

Wound exudate may have dark yellow, red and/or brown tones. Therefore,to appropriately mask these colours, an obscuring layer B3420 wouldpreferably shield light wavelengths of below 600 nm.

Measuring the reduction in absorption of light radiation at particularwavelengths may be performed by calculating:

%reduction=(A_(background)−A_(sample placed on background))/(A_(background))×100

where A is the absorption of light radiation at the particularwavelength.

Using this formula, using light at a wavelength of 460 nm, thepercentage of absorption reduction was calculated as shown in Table 3below.

TABLE 3 Appropriate masking Sample Absorption reduction at 460 nmobserved Sample 1 34% No Sample 2 77% Yes - partial Sample 3 69% Yes -complete

It has been found that materials that reduce light absorption by about50% or more will provide enough partial or complete masking of woundexudate (as judged by the inventors). Of course a complete maskingelement would preferably require a means for a clinician to judge thespread of wound exudate in the dressing below the obscuring layer B3420,e.g. the masking element not completely covering the entire dressing.For example, as described above with respect to FIGS. 41-49, a pluralityof viewing windows may be provided in the obscuring layer B3420 suchthat the spread of exudate in the dressing below may be adequatelyassessed. Alternatively a partial masking element may allow a clinicianto judge the spread of exudate in the dressing below without additionalmeans.

It will be understood that the wetting of a masking material (by exudatefor example) will also affect the masking performance of the maskingelement, since hydrophilic materials will allow chromophore-carryingspecies to travel through them more easily. As such, the absorptionreduction rate should also be tested on wet materials.

The above-mentioned Samples 1, 2 and 3 were also tested for theirmasking properties by measuring CIE L*a*b* values (a known 3-dimensionalmodel for representing colour space). The analysis employed Jascosoftware using the range 380 to 780 nm, stard observed 2 (deg),lightsource D65, colour matching JIS Z8701-1999.

Table 4 below shows the L*a*b* values found when Samples 1, 2 and 3 wererespectively placed over a black background. The results for the blackbackground alone and a white background are also shown.

TABLE 4 CIE L*a*b* Appropriate values recorded masking Sample L* a* b*observed? Black 0 0 0 n/a background Sample 1 (on 36.59 3.76 −1.80 Noblack) Sample 2 (on 71.76 −0.20 −1.08 Yes - partial black) Sample 3 (on70.64 −0.25 −1.23 Yes - complete black) White 100 0 0 n/a background

Generally, samples which lead to an increase in L* value will provide alighter colour tone than the reference surface, which is the maincontributor to masking a dark colour. From the values above, apt partialmasking materials will yield an L* value above 50, or more aptly above70.

However, completely opaque masking layers, such as for example a tintedpolymeric film, may cover the area to be masked with a darker tonealtogether, in which case the measure of L* is not relevant. Once againthese values should also be considered on wet material, for the reasonsstated above.

In addition to transmittance properties, the color of the obscuringlayer B3420 may affect the masking ability of the layer. In liquidpermeable embodiments of the obscuring layer, various colors aresuitable for masking the usual colors of wound exudate, while othercolors may not provide optimal masking of the exudate. For example, withreference to the CIE chromaticity diagram illustrated in FIG. 54, someembodiments of the obscuring layer, in a dry state, may be configured toyield a CIE y value of 0.4 or less and a CIE x value of 0.5 or less.Some embodiments of the obscuring layer, in a dry state, may have acolor of Bg, gB, B, pB, bP, P, rP, pPk, RP, O, rO, or yO on the CIE x, ychromaticity diagram. It will be appreciated that liquid impermeableembodiments of the obscuring layer may be configured with any color.

The obscuring layer B3420 can have one or more through holes located soas to underlie the suction port. Some embodiments may have a maltesecross B3421 or other shaped cutout underlying the suction port, whereinthe diameter of the maltese cross B3421 is greater than the diameter ofthe port. This may allow a clinician to easily asses—the amount of woundexudate absorbed into the layers beneath the port.

The dressing B3400 may also comprise a backing layer, or cover layerB3410 extending across the width of the wound dressing. The cover layerB3410 may be gas impermeable but moisture vapor permeable. Someembodiments may employ a polyurethane film (for example, ElastollanSP9109) or any other suitable material. For example, certain embodimentsmay comprise translucent or transparent 30 gsm EU33 film. The coverlayer B3410 may have a pressure sensitive adhesive on the lower side,thereby creating a substantially sealed enclosure over the wound inwhich negative pressure may be established. The cover layer can protectthe wound as a bacterial barrier from external contamination, and mayallow liquid from wound exudates to be transferred through the layer andevaporated from the film outer surface.

The cover layer B3410 can have an orifice B3411 located so as tounderlie the suction port. The orifice B3411 may allow transmission ofnegative pressure through the cover layer B3410 to the wound enclosure.The port may be adhered and sealed to the cover film using an adhesivesuch as an acrylic, cyanoacrylate, epoxy, UV curable or hot meltadhesive. Some embodiments may have a plurality of orifices for theattachment of multiple ports or other sources of negative pressure orother mechanisms for distributing fluid.

FIG. 50B illustrates a cross sectional view of the wound dressing B3400,displaying an embodiment of the relative thicknesses of layers of thedressing B3400. In some embodiments, the wound contact layer B3460 maybe flat and the top film layer B3410 may be contoured over the innerlayers of the dressing B3400. The spacer layer B3450 may be half asthick as the acquisition distribution layer B3440 in some embodiments.In some embodiments, the absorbent layer B3430 may be about 1.5 timesthicker than the spacer layer B3450. The obscuring layer B3420 may beabout half the thickness of the spacer layer B3450.

FIG. 51 illustrates a perspective exploded view of an embodiment of aflexible port or fluidic connector B3500 that may be used to connect anyof the wound dressings described herein to a source of negativepressure. The port B3500 comprises a top layer B3510, a spacer layerB3520, a filter element B3530, a bottom layer B3540, and a conduitB3550. The conduit optionally comprises a connector B3560. The distalend of the port B3500 (the end connectable to the dressing B3400) isdepicted as having an enlarged circular shape, although it will beappreciated that any suitable shape may be used and that the distal endneed not be enlarged. For example, the distal end can have any of theshapes shown in FIGS. 39A and 39B above. The distal end can also havethe shape shown in FIGS. 19A-19C above.

The bottom layer B3540 may comprise an elongate bridge portion B3544, anenlarged (e.g., rounded or circular) sealing portion B3545, and anorifice B3541. In some embodiments a plurality of orifices may beprovided in the bottom layer. Some embodiments of the rounded sealingportion B3545 may comprise a layer of adhesive, for example a pressuresensitive adhesive, on the lower surface for use in sealing the portB3500 to a dressing. For example, the port may be sealed to the coverlayer B3410 of the dressing in FIG. 50. The orifice B3541 in the bottomlayer B3540 of the port B3500 may be aligned with the orifice B3411 inthe cover layer B3410 of the dressing B3400 in order to transmitnegative pressure through the dressing B3400 and into a wound site.

The top layer B3515 may be substantially the same shape as the bottomlayer in that it comprises an elongate bridge B3514 and an enlarged(e.g., rounded or circular) portion B3515. The top layer B3515 and thebottom layer B3545 may be sealed together, for example by heat welding.In some embodiments, the bottom layer B3545 may be substantially flatand the top layer B3515 may be slightly larger than the bottom layerB3545 in order to accommodate the height of the spacer layer B3520 andseal to the bottom layer B3545. In other embodiments, the top layerB3515 and bottom layer B3545 may be substantially the same size, and thelayers may be sealed together approximately at the middle of the heightof the spacer layer B3520. In some embodiments, the elongate bridgeportions B3544, B3514 may have a length of 10 cm (or about 10 cm) ormore, more preferably a length of 20 cm (or about 20 cm) or more and insome embodiments, may be about 27 cm long. In some embodiments, theelongate bridge portions may have a width of between 1 cm and 4 cm (orbetween about 1 cm and about 4 cm), and in one embodiment, is about 2.5cm wide. The ratio of the length of the elongate bridge portions B3544,B3514 to their widths may in some embodiments exceed 6:1, and may morepreferably exceed 8:1 or even 10:1. The diameter of the circular portionB3545, B3515 may be about 3.5 cm in some embodiments.

The bottom and top layers may comprise at least one layer of a flexiblefilm, and in some embodiments may be transparent. Some embodiments ofthe bottom layer B3540 and top layer B3515 may be polyurethane, and maybe liquid impermeable.

The port B3500 may comprise a spacer layer B3520, such as the 3D fabricdiscussed above, positioned between the lower layer B3540 and the toplayer B3510. The spacer layer B3520 may be made of any suitablematerial, for example material resistant to collapsing in at least onedirection, thereby enabling effective transmission of negative pressuretherethrough. The spacer layer B3520 may comprise an enlarged (e.g.,rounded or circular) portion B3525, and may optionally include a foldB3521. In some embodiments, the elongate bridge portion may havedimensions in the same ranges as the bridge portions of the upper andlower layers described above though slightly smaller, and in oneembodiment is about 25.5 cm long and 1.5 cm wide. Similarly, thediameter of the circular portion B3525 may be slightly smaller than thediameters of the enlarged ends B3545, B3515, and in one embodiment isabout 2 cm. Some embodiments of the spacer layer B3520 may have adhesiveon one or both of its proximal and distal ends (e.g., one or more dabsof adhesive) in order to secure the spacer layer B3520 to the top layerB3510 and/or the bottom layer B3540. Adhesive may also be provided alonga portion or the entire length of the spacer layer. In otherembodiments, the spacer layer B3520 may be freely movable within thesealed chamber of the top and bottom layers.

The fold B3521 of the spacer fabric may make the end of the port B3500softer and therefore more comfortable for a patient, and may also helpprevent the conduit B3550 from blockage. The fold B3521 may furtherprotect the end of the conduit B3550 from being occluded by the top orbottom layers. The fold B3521 may, in some embodiments, be between 1 cmand 3 cm (or between about 1 cm and about 3 cm) long, and in oneembodiment is 2 cm (or about 2 cm) long. The spacer fabric may be foldedunderneath itself, that is toward the bottom layer B3540, and in otherembodiments may be folded upward toward the top layer B3510. Otherembodiments of the spacer layer B3520 may contain no fold. A slot orchannel 3522 may extend perpendicularly away from the proximal end ofthe fold B3521, and the conduit B3550 may rest in the slot or channelB3522. In some embodiments the slot B3522 may extend through one layerof the fold, and in others it may extend through both layers of thefold. The slot B3522 may, in some embodiments, be 1 cm (or about 1 cm)long. Some embodiments may instead employ a circular or elliptical holein the fold B3521. The hole may face proximally so that the conduitB3550 may be inserted into the hole and rest between the folded layersof spacer fabric. In some embodiments, the conduit B3550 may be adheredto the material of the fold B3521, while in other embodiments it maynot.

The port B3500 may have a filter element B3530 located adjacent theorifice B3541, and as illustrated is located between the lower layerB3540 and the spacer layer B3520. As illustrated, the filter elementB3530 may have a round or disc shape. The filter element B3530 isimpermeable to liquids, but permeable to gases. The filter element B3530can act as a liquid barrier, to substantially prevent or inhibit liquidsfrom escaping from the wound dressing, as well as an odor barrier. Thefilter element B3530 may also function as a bacterial barrier. In someembodiments, the pore size of the filter element B3530 can beapproximately 0.2 μm. Suitable materials for the filter material of thefilter element include 0.2 micron Gore™ expanded PTFE from the MMTrange, PALL Versapore™ B200R, and Donaldson™ TX6628. The filter elementB3530 thus enables gas to be exhausted through the orifice. Liquid,particulates and pathogens however are contained in the dressing. Largerpore sizes can also be used but these may require a secondary filterlayer to ensure full bioburden containment. As wound fluid containslipids it is preferable, though not essential, to use an oleophobicfilter membrane for example 1.0 micron MMT-332 prior to 0.2 micronMMT-323. This prevents the lipids from blocking the hydrophobic filter.In some embodiments, the filter element B3530 may be adhered to one orboth of top surface of the bottom layer B3540 and the bottom surface ofthe spacer layer B3520 using an adhesive such as, but not limited to, aUV cured adhesive. In other embodiments, the filter B3530 may be weldedto the inside of the spacer layer B3520 and to the top surface of thebottom layer B3540. The filter may also be provided adjacent the orificeon a lower surface of the bottom layer B3540. Other possible detailsregarding the filter are disclosed in U.S. Patent Pub. No. 2011/0282309and incorporated by reference herein.

The proximal end of the port B3500 may be connected to the distal end ofa conduit B3550. The conduit B3550 may comprise one or more circularribs B3551. The ribs B3551 may be formed in the conduit B3550 by groovesin a mold during the manufacturing of the conduit. During heat weldingof the upper and lower layers B3515, B3545 melted material from thoselayers may flow around the ribs B3551, advantageously providing astronger connection between the conduit B3550 and the layers. As aresult, it may be more difficult to dislodge the conduit B3550 out frombetween the layers during use of the port B3500.

The proximal end of the conduit B3550 may be optionally attached to aconnector B3560. The connector B3560 may be used to connect the portB3500 to a source of negative pressure, or in some embodiments to anextension conduit which may in turn be connected to a source of negativepressure. The distal end of the conduit B3550, which is inserted intothe spacer layer B3520, may be shaped in such a way to reduce thepossibility of occlusion.

FIG. 52 illustrates an embodiment of a wound dressing B3610 with aflexible port B3620 such as described with respect to FIG. 51 attached.The port B3620 comprises a conduit 3630 and a connector 3640 forconnecting the port to a source of negative pressure or to an extensionconduit. The dressing B3610 comprises an obscuring layer with one row ofeight holes in a linear arrangement, and is described above in moredetail with respect to FIG. 41. Although in this depiction the portB3620 is connected over a circular window in the obscuring layer of thedressing B3610, in other embodiments the port B3620 may be connectedover a maltese cross in the obscuring layer. In some embodiments, themaltese cross may be of a larger diameter than the port and may be atleast partially viewable after the port is attached to the dressing.

FIG. 53A illustrates a perspective view of an embodiment of thedressing. Although the configuration as depicted is similar to theembodiment of FIG. 45B, the dressing can have any of the constructionsof different layers previously described. Conduit B3710 is connected tothe dressing B3700 via port B3720, however other embodiments of portsmay be connected to the dressing, for example the flexible port of FIG.51.

FIG. 53B illustrates a bottom view of the dressing B3700. The viewillustrates a transmission layer B3730 and an acquisition distributionlayer B3740, which may be similar to the transmission layer B3450 andacquisition distribution layer B3440 of FIGS. 50A and 50B. In someembodiments, the perimeter of the transmission layer B3730 may beslightly smaller than the perimeter of the acquisition distributionlayer B3740. The view also illustrates one embodiment of a release layerB3750 similar to release layer B3480 previously described for use inprotecting the adhesive side of the wound contact layer. The releaselayer B3750 as illustrated is made of two separate layers of materialthat can be removed from the adhesive side of the wound contact layer bypulling on flaps attached to the release layer.

It will be of course appreciated that other dressing configurations arepossible other than a narrow central portion configuration, athree-lobed configuration, a four-lobed configuration, including, forexample, hexagonal or circular shaped backing layers for use indressings. As illustrated in FIGS. 31A-B, these embodiments may alsocomprise various configurations of slits, described previously, so as toenhance conformability of the dressing in non-planar wounds. Also, asdescribed previously, the absorbent layers of these embodiments may becolored or obscured with an obscuring layer, and optionally providedwith one or more viewing windows. Further, the domed ports of theseembodiments may also be replaced with one or more fluidic connectors ofthe type described below in FIGS. 39A-B, and vice versa. Additionally,all features and structures described for wound dressings with thewaisted portion configuration can be incorporated into any shape ordressing configuration as described herein.

Features, materials, characteristics, or groups described in conjunctionwith a particular aspect, embodiment, or example are to be understood tobe applicable to any other aspect, embodiment or example describedherein unless incompatible therewith. All of the features disclosed inthis specification (including any accompanying claims, abstract anddrawings), and/or all of the steps of any method or process sodisclosed, may be combined in any combination, except combinations whereat least some of such features and/or steps are mutually exclusive. Theprotection is not restricted to the details of any foregoingembodiments. The protection extends to any novel one, or any novelcombination, of the features disclosed in this specification (includingany accompanying claims, abstract and drawings), or to any novel one, orany novel combination, of the steps of any method or process sodisclosed.

While certain embodiments have been described, these embodiments havebeen presented by way of example only, and are not intended to limit thescope of protection. Indeed, the novel methods and systems describedherein may be embodied in a variety of other forms. Furthermore, variousomissions, substitutions and changes in the form of the methods andsystems described herein may be made. Those skilled in the art willappreciate that in some embodiments, the actual steps taken in theprocesses illustrated and/or disclosed may differ from those shown inthe figures. Depending on the embodiment, certain of the steps describedabove may be removed, others may be added. Furthermore, the features andattributes of the specific embodiments disclosed above may be combinedin different ways to form additional embodiments, all of which fallwithin the scope of the present disclosure.

Although the present disclosure includes certain embodiments, examplesand applications, it will be understood by those skilled in the art thatthe present disclosure extends beyond the specifically disclosedembodiments to other alternative embodiments and/or uses and obviousmodifications and equivalents thereof, including embodiments which donot provide all of the features and advantages set forth herein.Accordingly, the scope of the present disclosure is not intended to belimited by the specific disclosures of preferred embodiments herein, andmay be defined by claims as presented herein or as presented in thefuture.

1-28. (canceled)
 29. An apparatus to provide suction to a wound sitecomprising: a wound dressing comprising: a transmission layer configuredto transmit wound exudate; and a cover layer overlying the transmissionlayer and comprising an orifice; a fluidic connector attached to thewound dressing comprising: at least one film layer comprising a proximalend and a distal end; a fluid passage surrounded by said at least onefilm layer and configured to be in fluid communication with a source ofnegative pressure, the fluid passage comprising a porous materialencapsulated in said at least one film layer; and a sealing surface atthe distal end of said at least one film layer, the sealing surfacecomprising one or more apertures, wherein the sealing surface of thefluidic connector is positioned over the cover layer of the wounddressing with the one or more apertures in the sealing surfacepositioned over the orifice in the cover layer; a filter positionedabove the orifice of the cover layer; and one or more spacer elementspositioned below the filter, the spacer elements configured to supportthe filter and create a gap between the filter and the transmissionlayer.
 30. The apparatus according to claim 29, wherein the filter isadhered to at least one of the top of the cover layer and the bottom ofthe sealing surface of the fluidic connector.
 31. The apparatusaccording to claim 29, wherein the sealing surface and the orifice islocated in an off-center position.
 32. The apparatus according to claim29, wherein the orifice is directly connected to the transmission layer.33. The apparatus according to claim 29, wherein the filter isconfigured to substantially prevent wound exudate from entering thefluidic connector.
 34. The apparatus according to claim 29, wherein thetransmission layer comprises foam.
 35. The apparatus according to claim29, wherein the fluid passage is constructed from a flexible compliantmaterial such that fluid can pass through it if the porous material iskinked or folded over.
 36. The apparatus according to claim 29, whereinthe porous material comprises one or more materials selected from thelist consisting of foams, meshes, 3D knitted fabrics and non-wovenmaterials.
 37. The apparatus according to claim 29, wherein the sealingsurface is adhered to the cover layer by an adhesive.
 38. The apparatusaccording to claim 29, wherein the film layer comprises polyethylene,polyvinyl chloride, silicone or polyurethane having a hardness of 30 to90 on the Shore A scale.
 39. The apparatus according to claim 29,further comprising a source of negative pressure configured to befluidically connected to the fluidic connector.
 40. A negative pressuretherapy apparatus comprising: a fluidic connector comprising: a toplayer; a bottom layer comprising an elongate bridge portion, an enlargedsealing portion and one or more apertures; and a spacer layer positionedbetween the top layer and the bottom layer; wherein said top layer andsaid bottom layer are sealed together; a filter located adjacent the oneor more apertures in the bottom layer; and a wound dressing connected tothe fluidic connector, the wound dressing comprising: a cover layercomprising an orifice wherein the fluidic connector is sealed to thewound dressing and is configured such that the one or more apertures inthe bottom layer of the fluidic connector is aligned with the orifice inthe cover layer of the wound dressing; an absorbent layer; and anacquisition distribution layer configured to horizontally wick woundexudate as it is absorbed upwardly through the wound dressing.
 41. Theapparatus according to claim 40, wherein the wound dressing furthercomprises a wound contact layer, and wherein the acquisitiondistribution layer is positioned between the wound contact layer and theabsorbent layer.
 42. The apparatus according to claim 40, wherein thewound dressing further comprises a transmission layer between the woundcontact layer and the acquisition distribution layer.
 43. The apparatusaccording to claim 40, wherein the wound dressing further comprises anobscuring layer between the cover layer and the absorbent layer.
 44. Theapparatus according to claim 40, wherein the acquisition distributionlayer comprises viscose, polyester, polypropylene, cellulose, orcombination thereof.
 45. The apparatus according to claim 40, whereinthe absorbent layer comprises a superabsorbent material.
 46. Theapparatus according to claim 40, wherein the absorbent layer comprises afoam.
 47. The apparatus according to claim 40, wherein the absorbentlayer is positioned above the acquisition distribution layer.
 48. Theapparatus according to claim 40, wherein the spacer layer comprises oneor more materials selected from the list consisting of foams, meshes, 3Dknitted fabrics and non-woven materials.
 49. The apparatus according toclaim 40, wherein the filter is positioned below the spacer layer. 50.The apparatus according to claim 40, further comprising a source ofnegative pressure configured to be fluidically connected to the fluidicconnector.